All limited time … not sure how long - Scribblenauts and Contre Jour are must have games in my opinion:
Best deals:
Scribblenauts for 0.99 http://itunes.apple.com/us/app/scribblenauts-remix/id4448447…
Contre Jour HD for 0.99 http://itunes.apple.com/us/app/contre-jour-hd/id444085845?mt…
Also good:
Puzzle Game Tanzen free http://itunes.apple.com/us/app/tanzen/id286331900?mt=8
Street Fighter IV for 0.99 http://itunes.apple.com/app/street-fighter-iv-volt/id4328495…
Other deals:
Gameloft Sale http://ax.search.itunes.apple.com/WebObjects/MZSearch.woa/wa…
New World Colony free http://itunes.apple.com/us/app/new-world-colony/id395137626?…
Grand Prix Story 0.99 http://itunes.apple.com/us/app/grand-prix-story/id456976375?…
Shadowgun 0.99 http://itunes.apple.com/nz/app/shadowgun/id440141669?mt=8
Peggle 0.99 http://itunes.apple.com/nz/app/peggle/id314303518?mt=8
World of Goo (non HD) 0.99 http://itunes.apple.com/us/app/world-of-goo/id415997203?mt=8
they will be free, eventually