What Pedal / Cleat Should I get?

Crank Bro's Quattro road pedals are great - no-clog, low profile cleats (using the available composite adapters) that afford respectable grip when running in transition.

Double-sided with 4 points of entry (like their regular eggbeaters) make clipping in/out a no-look snap. They can be fit to most types of bolt patterned shoes with the available adapters as well. Quattros are not compatable in any way with SPDs.

I like the SPD cleats with more of a mountain bike shoe that lets me move around a bit more freely off the bike than a true road shoe.  Never had problems with grass or mud.  Comfortable, easy to get in and out of the pedal, easy to replace and as noted with regard to a spinning class, versatile.

Aside from all of this, I'll join in and echo your question a bit ... I've really only used the SPD cleats and was wondering if there were advantages to switching to other cleats.  Weight is not an issue to me, so are we just talking about personal preference and/or brand loyalty here, or are there true advantages out there with the various cleats, shoes?

Comparisons of pedals/cleats could include: weight, as you mentioned, in addition to ease of entry (single sided vs. double sided, from 1 to 4 points of entry), amount of float and whether the float can be adjusted to suit the individual (some can, others cannot), amount of routine maintenance required (some requiring regular maintenance/cleaning/lubricating of the mechanism, some requiring none), whether they hold debris or shed it well, whether it's important to be able to run in the shoe (in transition), price (especially when you get into titanium and carbon), and even options like different colours to match your bike/kit.  

I cite my own example of starting out with SPDs, switching to Speedplays, then after much homework, settling on Quattros because of most of the reasons cited above as improvements over the previous two pedal systems. 

Ultimately, it's to each his own, and can b a matter of Ford vs Chevy. 

I used to have Shimano SPD on my road bike but moved them to my MTN bike and upgraded to Look pedals. I have to say I prefer the look's on the road bike. The stiffer shoe is awesome, and I do not feel the pressure I used to feel on the bottom of my foot during long rides I used to get with SPD.

Bottom line any of them will work. I went with SPD initially based on cost... Any clipless pedal is better than cages and straps.

For just the biking, I love the Speedplay pedals I have on my bike.  I'll be the first person to admit that they aren't the best for running in during transition, so if you don't have the rubber band trick down yet (I don't...someday though), they might not be the easiest to start with.

Note: just re-read your post and noticed you said on your hybrid bike.  I keep SPDs on my hybrid, and use those same shoes when I take a spin class any place where I don't take my own bike and trainer.  They're definitely low profile and easy to run in, especially compared to my Speedplays.  I don't know any cleat that won't pick up mud and grass if conditions are bad enough though.  The SPDs are also relatively inexpensive.