PC to Mac migration

[muzikul]

I'm trying to figure out what all I will need as I move from a PC to Mac, and where to find it all. My main concerns are getting all of the necessary codecs that don't come with OS X, and useful software that I've been using for years. Specifically...
DivX
XVID
WMV - can I play these files on a Mac?
VirtualDub
TMPEnc
DivFix

Also, what alternatives to QuickTime are recommended for a video player? Thanks for the help!