Jenn, you will get a different answer from everybody who responds. Someone else's most favorite juice of all time may well be your most hated juice. I've tried juices that had rave reviews from lots of people, and I hated them. Likewise, I like some juices that others hate.
Unfortunately, it just works that way. The only shortcut is to go to the General E-Liquids subforum here and read a LOT and try some small sample sizes of some of the juices that sound good to you.
Regardless of how good a juice sounds, don't go buy a big bottle of it. I personally know a little something about the disappointment of opening that 30ml bottle of what I thought was going to be great, and then saying "Yuck."