I voted Sonic, Xan Kriegor [and yes, he is in the game], and 'Other'.
'Other' includes a whole host of characters, really. I tend to have many favorite characters.
Commander Keen - I've liked the game and character so long I have forgotten the true reasons why; but there must be a reason. And anyhow, I still do. From Commander Keen, of course.
Isair - From Icewind Dale II. Reasons? Unclear, as usual, except that I find raving psychotic cambions humorous. Don't you?
Darth Revan - Okay, these reasons get a little complex. And also would have to have a 'spoiler' warning slapped on them if I listed them fully. So we shall leave it at that.
Knights of the Old Republic.
The Kernel - Tron 2.0. Again, I don't know precisely why.
Hmm... that is all I can think of right now, so it'll have to do.
The list gets longer if you include characters I've created, of course. However, I do not think that is what you meant.