I need some suggestions

Well, regarding RPGs, I suggest that you don't jump on the hype train, but try some excellent Lites instead. I mean, everybody has been recommending Zenonia since forever, but IMHO it's atrocious control scheme just sucks whatever fun it could have had right out of it.

Anyway, I recommend trying the Lites for:

Undercroft. A fun turn-based RPG similar to Eye of the Beholder (party creation, puzzles).

The Quest. A huge, free-roaming RPG similar to the older installments of the Elder Scrolls series, only with turn-based combat.

As a bonus, if you like these games, you won't have to re-start from the beginning once you upgrade - the saves are transferable.

Battle for Wesnoth. More of a turn-based strategy game, but with strong RPG elements.

The usual suspects like Dungeon Hunter and Zenonia also have Lites.

Puzzle Quest may be another interesting option - IMHO it is a great genre blend. If you like the Lite, you'd have to get to get the "Chapters 1 and 2" version of the full game, which is a complete port of the PC version.

As to platformers, I am not a big fan of them, but I fell in love with Sway, which is fairly unique. It has a Lite, too.

 

Well, I've purchased about 10 pages of paid apps and I delete most of them. Here are the few worthy enough to stay on my phone:

Boost 3D is one of the best games I've ever had (all of these are). It's pretty much a better version of Fieldrunner. The difference is this gives you a much larger feeling of speed. There's nothing better than the feeling of zooming through a tunnel dodging spiraling cubes in split seconds. I suggest you watch some YouTube videos of it.

Labyrinth 2 is the game with the most replayability on the Appstore. And fortunately, it's a good one. It's worth much more than $5, I promise that. Download the lite version Labyrinth and if you found any of those levels remotely fun, you'll fall in love with Labyrinth 2.

Soosiz is a full-length platformer that you won't beat for a long time. It's pretty much a 2D version of Super Mario Galaxy, one of Nintendo's greatest ideas. When I first started playing Soosiz I thought that the levels were rather simple and boring. I kept playing out of interest and I started to see that Soosiz is actually a very fun and challenging game. You'll have to wait to world three but once you get there you'll be pleased. I'm a huge fan of Super Mario Bros (Super Mario World is still my favorite game, period). If you like Super Mario Bros, you'll love this.

Minisquadron is awesome and you already have it so you'll see for yourself.

Oh, and if you like chess at all, Animal Kingdom is a cool mix of Chess and Stratego