Best value in buying speed...

There are a lot of caveats that come with that study.  For example, don't move your head or you just lost ALL your advantage from your helmet (now it's added drag).  Oh, and a disc cover is under $100 and works as well as a disc. 

How about: swim lessons, bike fit, increasing your flexibility so you can ride more aero, losing some weight?  Lots of things offer better value in "buying" speed than in buying race wheels.  (But new bikes/wheels/toys are cool )

Or practice smart training >>> either spend some money to educate yourself and learn how to take adavante of your available training time or hire a GOOD AND EXPERIENCED coach. That will be your best ROI

I'm thinking #1 best value for most people comes in improving the engine (including losing weight, when applicable).  Beyond that, from what I read, aerobars can help.  I suppose I've been silly not to buy some. 

That article was great.  I especially appreciated this cute quip: 

Jason Sears, fourth-year Ph.D. candidate: Collegiate cycling is a gem; the atmosphere is incredible. We have men and women on the same team--which is good because some of us wouldn't have girlfriends otherwise.

Rick specifically said "swim/bike/run" were a given, and he is talking hypothetically here. I took it from the OP that he wanted to discuss/debate gear and things you can do to be more aero. Not about training and coaching.

That being said, I heard that a bottle on your seat tube is more aero than not having one.

The items I mentioned are not just "swim/bike/run" more.  They are investments of either time or money that will give you more speed in a triathlon.  Several of them specifically can help you get more aero on the bike (fit, flexibility, weight loss).  I continue to note that a disc cover is one of the best "bang for the buck" pieces of gear for you to "buy speed".

Oh, and the water bottle is for round tube bike frames.  Not sure it works for all the "aero" tri frames people are riding.

OK.  Just don't try to look behind you then.

FWIW, I'm not trying to dismiss an aero helmet as another tool worth exploring for those looking to shave off some more time on their bike.

I often wonder if 90% of the amateur triathletes are good enough to even notice the difference in their time when wearing cycling gloves and not wearing cycling gloves.  I'm thinking the local AG winner prolly may get what, a 10 second advantage over an OLY course due to less drag created by a disc wheel?  Please....This is akin to debating the newest golf ball for the average 18 handicapper.  Only the elite players in the world are going to notice or feel the difference from last years new Titleist to this years.

I'm SO with you Xan!  I'm definitely getting the most out of my entry fees!

If you are in contention for an AG placing that 10 seconds can be a big deal. Not to mention the time to put them on. I got 2nd in my AG in a race last year rather than 3rd by 15 seconds. Why? Because I had Yankz and she didn't.

Some of this free speed stuff works.

Actually, you may be looking at as much as a 1mph increase in speed, which is what I (and others) have anecdotally experienced. If you increase your average from 22mph to 23mph on a 25-mile coure, you save 3 minutes.

The OP was trying to help me understand where the best bang-for-the-buck for your tri dollar lies for improving speed, and results.  One of the first purchases I made to improve speed was a bike, then wheels.  In hindsight, I'm not sure they were the most cost-effective.

And as I read more, I learned that some pretty small things can make a huge difference, as can supplementary 'services',  like a coach or nutrition plan, or even money on a race entry fee because it guarantees you a long brick and invaluable learning.  I also learned that some really hyped stuff offers marginal improvement (like carbon water bottle cages, for instance).

I think if I could, I'd set up a scenario (like oly distance, entry level tri bike, mop'er) and try to look at all the gear, services, or whatever you could buy, and try to put a time savings and cost on it, and with a little math you could come up with $ / unit of time saved.  Everything from upgrading frame and components down to yankz, from aero drinking systems to rubber-banding your pedals, from coaching for 3 months prior to race wheels.   That way I'd have a much clearer picture of the effectiveness of my tri dollar.  I don't know if that's too complicated, though. 

I need to think this one through.

I think it's also important to consider long-term investment vs. instant gratification.  I'd say hiring a coach and training/racing with a power meter (assuming you kno how to take advantage of it) are the best long-term investments.  This is working under the assumption that you've already taken care of the basics...have a decent bike with a professional fit and have spent 6+ months of basic training.  But you've got to be willing to incest 6+ months to start realizing the benefits of either.  I would consider this "investing" in your future.  With other goodies like race wheels, aero helmets, aero bars, racing flats, and wetsuits you get the advantages immediately...you're "buying speed".  Some people have the opinion that it is a waste of money to spend $$$ on these things for the average triathlete.  I don't totally agree but it really depends on how much disposable income you have.  Personally, I'll do everything I can within reason to shave a little time.  Think about everything in totality.  If you do/buy 10 things that each save you 30sec on average then you just cut 5min off your race without any additional fitness gain.  I'm the last person to suggest taking the easy way out and not training better/smarter but it seems silly to pass up free speed if you have the means to get it.  My own personal ranking of "bang for the buck" for the average triathlete woud go somethihg like this (ignoring the long-term investment options of coaching and p[ower meter):

• professional bike fit
• aerobars
  
• swim lessons (this could be considered a long-term investment but I think that anyone without a swimming background can make immediate gains from 2-3 sessions with a good swim coach)
  
• wetsuit
• aero helmet
• aero wheels
• anything to reduce the weight of your pedals/cleats/shoes, running shoes, bike.  I've got this at the bottom of the list because it typically means replacing perfectly good gear with something a bit lighter.  I wouldn't go here until you've hit everything else or unless a piece of gear needs to be replaced anyway.

I can't really compare the long-term investment type things here...it's like apples to oranges IMO.  Again, if you have the means ($1000+ for a power meter or CompuTrainer and $100-500/month for a professional coach) and you are looking at your training as a process and are willing to be patient then that is probably the best INVESTMENT.  I approach my training with more of a long-term approach.  As a result I have to accept not being as fast as possible right now for the pay off of maximizing my potential in 3-5 years. 

There are also a few free things that can be done...lose 5lbs, perfect your transition, learn to draft effectively on the swim, where you put your water bottles, learn to stay in the aerobars while drinking and eating...most of these are skills or planning related. 

Just my thoughts. 

The other side of this sword, the real reason this belongs at the bottom of the list, is that when you replace anything to save weight the performance gains will be extremely marginal at best. Not only do you have a high cost but you have a tiny benefit. For only a few will those gains be worth the cost.

Agree.  There are benefits to reducing weight, especially in your wheels and shoes/cleats/pedals, but they are small and we're talking $250 for a set of titanium pedals when your regualr pedals are just fine.  Still though, if I'm in the market for new pedals and I can afford to spend $250, I'm getting the titanium Speedplays...and I did   Were my pedals worth it...no idea but they didn't break the bank and I know I'm taking advantage of every opportunity to shave seconds...I'm kinda anal like that. 

OK...this may sound dumb.  Just attribute it to me being a complete beginner (even after a year).

Any dollars spent on learning better technique will save the beginner lots of minutes out there on the course.  Some books or dvd's about swim, bike, or run technique really make a difference. 

On my Oly this summer, I got out of the water and felt really good, but my time completely suc%ed.  It wasn't a conditioning problem, it was poor technique and sighting.  Next year at this same race I hope to knock at least 15% of my swim time...with the same fitness level, but improved form. 

The bike is the segment that can really be improved with better technique (or so I'm told).  The investment for better technique is small...a few bucks; but the return is great.

(Thanks for all the thoughtful input on this thread.  Good stuff!)