I think it's a toss up between the DS and the 360.  PS2 had an especially good year, but really, who expected it not to have one?  The DS had a stellar lineup, and it's really proven it to be the Little Engine that Could.  360 had a great first year, maybe one of the best first years ever for a console.  It got off to a slow start, and while software was never there in quantity, there was a steady stream of extremely high quality and/or interesting titles.  GRAW, Oblivion, Dead Rising, Viva Pinata, GoW (although it's not my cup of tea), Rainbow 6 Vegas, CoD3 (the multiplayer makes up for the ho-hum campaign).  It only loses points for the console's questionable hardware reality, the reason I can't honestly recommend the system to my friends.