Is QT Pro necessary when using DV, 4x3 and anamorphic?
Is QT Pro necessary for HDV work?

Vegas 8.0b
Windows Vista
MacBook Pro

QuickTime Pro is not necessary, especially if you have a good editing program like Vegas which will handle your requirements quite easily. On the Mac side, QuickTime Pro might be more useful, but you might think about getting Final Cut Express which can handle all those formats (except for 24p).