I'm taking the leap from analogue and capture cards to DV and Firewire...

Just wondering, I know that captured PAL DV is 756X288 in the DVAVI codec, which is around a gig per 8 minutes (I have 14 gigs freespace :P)

is it possible to capture DV into uncompressed AVI and is there a big difference between this and DVIAVI?

DV-AVI is about 13 Gig per hour. Your size is wrong. PAL is 720 x 576.

Ooops... Thanks for pointing that out :)

Is it possible to capture to Uncompressed AVI though? Is there a big difference in quality between U-AVI and DVAVI?

Not without special hardware. However, If you're taping on MiniDV tape, you're already in DV so there's no advantage to capturing in uncompressed. Capturing DV is equivalent to doing a file copy from tape to hard drive. "Capturing" is kind of a misnomer.