First off I love Nolan north, but I was wondering who people would want to voice their ghost if they could get anyone. Personally I'd go for Samuel L Jackson.
[spoiler]You woke the hive motha-blam!-a!
Gimme time bitch this sequence is complex. An I ain't that good at math mother -blam!-a![/spoiler]
Wow. A lot more responses than I thought! Another that hasn't been mentioned : Nigell Thornberry. And he would say "smashing" at the end of every mission or crucible match.
Or how about claptrap? (Borderlands 2)