Solitaire Siege is a pretty good solitaire card game. It's basically Pyramid Solitaire with some twists and bonuses. I got it last time it was free and played it a whole bunch.
Dark Harvest is pretty fun. I got it one of the two times it was free: http://www.appshopper.com/games/dark-harvest
It's like Puzzle Bobble but instead of being fixed, the pieces you're shooting at are often floating around. Then when you hit it with a piece that affects the momentum and shifts...
To be fair, Angry birds came out in December so he may not have played it yet (and it was 1.0, first update was in Feb) and Sword & Poker came out on Jan 7 2010 so it wasn't even eligible to be on that list.
I bought this game about a year ago when it was briefly back in the store. It's a great game once you get used to the controls. Definitely worth $1.
Two tips that made me enjoy it a lot more was learning that 1) you can rotate the view to landscape with a two-finger spin and 2) double tapping...
DropZap is free temporarily. I actually paid $1 for it a month or so ago and I'd highly recommend it even at $1. It's incredibly addicting and the strategy is deeper than it seems at first glance.
http://appshopper.com/games/dropzap
Traffic Ninja is free for 24 hours. I tried it out quickly and it's alright but not my thing. http://itunes.apple.com/us/app/traffic-ninja/id351266002?mt=8
Gave the lite version a try and it seemed odd but had promise. I bought the full version and it does a much better job slowly ramping up the difficulty. A lot of the patterns you end up making look really neat as well. Definitely worth a buck if you're into these types of puzzles.
I was just in your store last night trying to get them to price-match the DJ Hero thing! (http://www.cheapassgamer.com/forums/showthread.php?t=241467) Almost got it too. The customer service guy was willing but the LOD wouldn't allow it without a real ad.
I may ask for your help on Black...