While I'm hardly an aficionado yet, I find the stuff I generally like the most is nicaraguan.
That being said, I have not refined my tastes enough yet to distinguish binder and wrapper flavours (like being able to say "man, this cigar would have been better with a nicaraguan binder and an ecuadorian wrapper").
And as I've said a few times before, I like Cubans, but to me they're generally overrated. It seems like more of a "forbidden fruit" thing for American smokers - they're illegal, so they're the best!