SERIOUSTHRED REQUIRES SERIOUS AANSA:::in terms of pure aim, probably joker / ulti / me.
Best 'player' is hard to distinguish so in all round BRAINZ/knowledge i'd put me/ulti first then mess/gtrain/timmy "rainbow" rootz second. (yes ulti actually does revive in team vs team matches.) I don't think i've seen Joker on etpro :S . I suck now though cos I don't have access to a good setup.
Mess + G train might not have the best aim but they are great team players.
Anyway it's hard to judge but for what you're asking, as Joker said I can remember plenty of times smashing the players listed and i remember getting smashed by them.
However.... like you said 'the best player on OZ' which basically means the best pubwh0re so JOKER gets my vote cos he tears up etpub. ( i remember when he was bad lol)
If Joker played earlier and more competitively he would be #1.
etpro > etpub