Broad question, there. It all depends on how you'd like to use it (clitorally? vaginally? anally?), how strong you like it, how large you'd like it to be if you're inserting it, whether you want something hard or soft, etc. Any ideas on what you'd like in any of those categories? If not, you might just try a few really simple toys (like a traditional vibe or a bullet) and work out what you do and don't like, and go from there.
If you're just looking for random suggestions, though, I'll say the Bimini Ocean is my favorite vibrating toy.