I did think Tiny Heroes was impressive, the War on Terror is humorous, Elder Sign is a worthy contender, BattleHeart is highly replayable (and while it is one of those 'RPG-like' games I described, the gameplay mechanism is quite fun), GodVille is truly unique (and funny & free w/o IAP), PuzzleQuest is awesome, Protector was interesting/challenging, Anomaly was fun but lacked replayability, Neuroshima Hex is a fav, Ascendancy has potential as a 4x (but UI was challenging), Battle for Wesnoth should be a 'genre breaker' (amazing strategic combat), and I also liked The Lord of the Rings: Middle-earth Defense (had some good value for unique LOTR character based TD game),
Disappointments were King of Dragon Pass (which had a great review but was less than thrilling), King Cashing (supposedly unique/amazing game, but I found it lacking), Legend of Yore (an 8-bit Rogue-like w/o anything beyond hack & slash), & Mage Gauntlet (great review, less than exciting 8-bit retro game). Also bought Chaos Rings awhile back & found that very disappointing.
I've also tried a bunch of CCG games for iPhone, incl the 'big' Shadow Era (ok game, hate the clumsy UI), Dungeon Solitaire (good fun, some strange new cards), Kard Combat (was fun for a few plays, then boring), as well as Cabals (strategic game with potential, UI was awkward & heckling IAP is annoying), Orions 1 &2 (both fun, dev's not so great), Stack & Deploy (interesting CCG-like game w/action elements, UI takes practice).
Big fan of Speedball 2 (fun!), Words w/Friends (my g/f is hooked & have a few regular ongoing games, new IAP is annoying), Dungeon Defenders & Defender Chronicles (fun twists on TD),

Dungeon Raid may be my all-time favorite game -- the developer started with an excellent game and improved it, dev is very responsive and committed to their community of players, and the mechanic is a lot of fun AND the sounds are great (and I can play my own music behind it).