Wondering which ones people like the most.

There is no best, and most people don't have a clear favorite for all times anyway. If you want to do some research, there are a lot of similar threads to this one floating around right now:

http://www.gamesas.com/topic/1402254-which-enb-do-you-think-is-the-best-and-why/
http://www.gamesas.com/topic/1403742-best-performing-enb/
http://www.gamesas.com/topic/1404333-enb-with-minimal-fps-loss-whats-yours/

I am currently using http://skyrim.nexusmods.com/mods/21912 for a more vanilla Skyrim look, and when I like bright colours I use http://skyrim.nexusmods.com/mods/20570 (both by the same dev team). That said, as far as these things go, they are COMPLETELY a matter of taste, and screenshots rarely do justice. Also they look different depending on your specs (a lot come with optional levels of detail), and most can be tweaked easily. Just experiment. They tend to be relatively small downloads, and uninstalling is generally pretty simple.

EDIT:
Also, I strongly recommend playing with different AA algorithms. I am personally partial to MSAA over the obvious others, but a lot of people seem to say SMAA looks the same for less performance. I honestly run SMAA and 2x or 4x MSAA simultaneously because I tend to think that's the performance sweet spot. That said, I am running a pretty powerful rig, and keep a consistant 45-55 FPS outdoors with these settings.

Finally, consider what OTHER visuals you'll be adding. For instance, Realistic Lighting With Customization is amazing, but will look different with different ENB's. It's literally ALL a matter of taste, haha.

What running4cover said ^

It is so much down to personal taste that I'm always hesitant to recommend, the best bet is to try out a few yourself and pick the one that suits you best.

That said, I very much like http://skyrim.nexusmods.com/mods/20570 and http://skyrim.nexusmods.com/mods/15983. I like a more colourful saturated world (Vibrant provides that, True VIsion less so but has other benefits), but if that is not for you there are others that go in the complete opposite direction and provide very cold looking environments that are atmospheric in a completely different way - if that is your thing, then something like http://skyrim.nexusmods.com/mods/21350 might be to your taste. It's hard to say, because it's so dependent upon personal aesthetic choices!

I think Countervibe ENB is the best so far. Best balance of vanilla and vibrancy IMO:

http://www.youtube.com/watch?v=ig-CyMukzcU

Your taste is the closest to mine, I think. I like Vibrant END, just wish it was toned down maybe 15%. Looks great though.

I like Cool Quiet, Vanilla Enhanced and True Vision for different reasons.

Actually, that does look pretty darn good. I'm giving it a go.