iDracula is my most played game of all time, but recently I've been hooked on Modern Combat and Inkvaders.
I played Payback and Baseball Superstars 2009 a ton at one point. Lately it's been 9 Innings Pro Baseball 2009 and Gangstar.
I know you asked for just 1, but I've got 3 that are way ahead of all the others: 1. Defender Chronicles 2. Chess with Friends 3. Words with Friends Defender Chronicles is easily tops, but all the times I open up CWF and WWF to make my next moves add up over time, so I'm sure they're 2nd and 3rd.
When I first got my ipod I played aurora feint all the time then I played these non stop for at least a week after I got them Tyrian SIIG Meteor Blitz Blue Defense The Creeps Drop7 Bejeweled Match 3D
at the moment, its probably inkvaders all time is probably car jack streets due to the real time side of the game-50000 dollars every week-im actually a bit tired of playing it! ill probably be addicted to chinatown wars(im addicted to it on ds) when it comes out tho soosiz might be addictive
Lately I've been playing a metric crapton of Meteor Blitz and Canabalt. Mostly while on the can. Mostly.