Well, I have been through various phases on my iPad. At first I bought small games for quick consumption, as that was what I always did on my iPhone and it has served me relatively easy while spending a minimum of money. But as I quickly found out, I use and expect very different things on my iPad than my iPhone (and console). The previously fun small games were in fact quite boring. They serve as time wasters on my iPhone, but I had no need to waste time on my iPad. I wanted a greatet level of immersion.
So i started reading reviews, forums etc. Eventually I ended up buying some "hardcore" games, but quickly found myself asking - why don't I enjoy games like these on my PS3, where the experience is almodt always greatly enhanced.
Lately, I seem to have found a way to enjoy games on my iPad. I focus on less games, but look for ones with some strategy and immersion that is unique. I usually have 30 minutes or so sessions on my iPad. I also look for games that are designed for touch. I don't like the virtual analogue sticks and other gimmicks.
Right now I'm thoroughly enjoying Kingdom Rush with Battleheart and Civilization waiting afterwards. Othr games that I would recommend are Hunters and World of Goo.