A couple recommendations off the top of my head:
- If you like pinball at all, try either Pinball Arcade
(for re-creations of actual pinball tables) or Zen Pinball
(for crazy tables using licensed properties like Star Wars, Marvel, etc.). At last count, I've put over 150 hours into Zen Pinball, and that's only going to increase with the release of 4 new Star Wars tables tomorrow.
- Final Fantasy Tactics: War of the Lions HD
is a brilliant port of the PS1/PSP game (I think it's the best version of all the platforms). The recent port of FF 6 is also very well done.
- The port of Star Wars: Knights of The Old Republic
- Nimble Quest
is a blast. it's the old "Snake" game from mid-90's cell phones, combined with an RPG.
- Lords of Waterdeep
is a perfect port of the board game.
- There are tons of CCG games available. Hearthstone, Ascension, Magic, Dominions, etc.
is one of the best casual games available.
is a Zelda clone that got excellent reviews.
is an Infinity Blade-esque fighter that is far more fun than it has any right to be. One of my favorite iOS titles from last year. While not really my thing, Infinity Blade 2
is certainly worth a look.
Touch Arcade has a Top Reviews
page where you can filter through the best reviewed games. I find them to be the best iOS review site, although I do think they tend to score a bit high.