I played the first two on the 360, so I might as well finish up the trilogy there. I am not going through at least 10 different playthroughs all over again just to play the game on PC or PS3!
The PC route at least would be relatively easy, with Gibbed's ME2 Save Editor
(or the modified version
, for that matter).
I will also be finishing the trilogy on Xbox. I received a free PC copy of ME2 when I purchased a new copy of Dragon Age II
for Xbox, but outside of SWTOR and STO I'm not much of a PC gamer.