From what I hear, the Aspire Nautlilus is probably the best mid-range
tank out right now (high end being RBAs and such), though I haven't tried one myself. Heard good things about the Kanger Aerotank, which says something after the horrid reception of the Protank 3 (don't
buy a Protank 3, money better spent elsewhere).
I have an iClear30X.I that I like pretty well - its hits good, and no leaking problems as of yet (had it for 2-3 weeks). Also, I love the SmokTech Pyrex DCT...it's a cheapie cartotank, but I like it.
My favorite clearo at the moment though (and out of all that I've tried), is the iClear30S. It's got a center post that holds the wicks, kinda like a cartomizer design, and it just produces great flavor and vapor for how inexpensive it is. I would recommend that, honestly, and I think it's about the same price as if you bought one of those iClear30B's standalone...but yeah, the S definitely hits better than the B.