For your edification, IGN has helpfully posted a list of all the different media formats that the PS3 can be expected to play at launch.

VIDEO
• MPEG-1
• MPEG-2 (PS,TS)
• H.264/MEPG-4 AVC
• MPEG-4 SP

MUSIC

• ATRAC (.oma .msa .aa3)

• AAC (.3gp .mp4)

• MP3 (.mp3)

• WAV (.wav)

IMAGES

• JPEG

• GIF

• PNG

• TIFF

• BMP

AVI and DivX seems like the suspiciously missing contender there, which is a bit of a bummer. And what about Ogg Vorbis?

Naturally, any type of refractive, laser-read disc under the sun will be supported... except, of course, laser discs, which are to DVDs what 8-Tracks also are to DVDs. Florian Eckhardt

PS3 Formats [IGN]