My favorite butterfly vibrator is the Audi-Oh... it straps on with the usual elastic straps so it fits snugly against the clitoris, and has a bullet vibe that silps into it. It's wired to a small remote.
The cool thing about it is you can set it to respond to sound, or use it with the usual speed dial most of them come with. You can use it with music, or your voice... or you can breathe on the little microphone on the remote and it will vibrate from your breath! It's kind of cool!
As for vibes, I like the silicone vibrators. The silicone is nice and soft, kind of pliable, and feels good when it's inside your pussy, or when it's being rubbed on your clit. These feel SO much better than those dumb plastic smooth vibes.
I think the thing is to keep in mind that women usually like the vibration on their clitoris... it's nice to have something big inside, but most women can't have an orgasm from internal stimulation only. Therefore, the little bullet vibes or things like the Fukoku are really awesome, as opposed to some huge realistic looking cock vibe.
I actually review sex toys, and my fav vibe so far is here:
http://reviews.monicaweb.net/gigolo.php
People have mentioned some really good shops... here's a list of the places I like so far:
http://www.ilovexor.com
http://www.wildinsecret.com
http://www.libida.com
http://www.babeland.com
http://www.vixencreations.com
http://www.funfactory.de