Valet Hero is my favourite by far, I find it more fun and addictive than flight control, harbor master etc. http://itunes.apple.com/gb/app/valet-hero-pro/id355664013?mt=8
Furballs! I don't know why this game does not get more attention http://appshopper.com/games/furballs
my all time favourites are flight control harbor master monkeys in space aqua globs super 7 33rd division other good ones (just not among my favourites) are harbor havoc 3d, lion pride, draw race, car mania (yep, I bought all these line drawing games...)
Some other good ones not mentioned yet include: 2360 - Battle for Cydonia Airstrike Defense AstroSerf Boom Brigade Fare City Flock Control Into The Blue Parade Patriot Jets Sea Captain Taxi Jam Wildfire Fighter
Just to let you guys know, Fare City is back on sale under the Finkly Interactive label and is free for the next three days. Get it while you can...
Trace was really good. it involved you being a stick figure trying to navigate through an obstacle course (about 100), and then you had to draw lines to get through the obstacles.