lets see, I have quirky tastes so idk if my pick would be ur drug of choice. N.B this is not in order of preference
1. The World Ends With You (Brilliant use of the stylus + a Gantz/The ring spin to it makes this an instant winner)
2.Super Mario (one of the few kiddie type games i really enjoy)
3.CrossworDS (this i got for the missus but..it..got..me...)
4.Final Fantasy Tactics A2 (Great ORIGINAL SRPG --i stress on orginal cos Disgea DS is a remake, and i sorta like the psp version better)
5.Final Fantasy IV (the other remakes sucked IMO and crystal chronicals was made for the teletubbie generation...waiting for FFV and VI though)
6.Super contra (dude, ITS CONTRA!!!!)
7.Sonic Dark brotherhood (just started playing, looks promising despite my inexplicable despise of sonic and his crew)
8.Dragon quest -insert version here- (nice rpg)
9.Professor Layton and the curious village (really enjoyed the riddles and other elements of gameplay in this one)
10.Pokemon -insert version here- (not a personal fav but deserving of a space regardless)
there are others, these just spring to mind right now