The limit for FAT32 is 4GB. Not sure about Apple formatted drives, although I've yet to run into a limit despite uncompressed video file sizes in the 20+ GB range.
Quicktime used to have a 2gig limit, but that seems to have gone away. Some file formats have limits. WAV files are unstable over 2gigs, though there is a modified version that can be larger. Embedded OMF files can't be over 2 gigs. And I though the FAT 32 limit was 2 gigs? I know we had problems going from Mac to Windows with FW drives because the FAT file system had limits.