My mate has a 360, but doesnt run it on a HDMI cabel. Can he, or are we being dumbasses?? If so where can we get one??

Cheers

the 360 does not have a true hdmi output hence the extreme edition, but your hd details for what it has and info can be found here:
http://www.xbox.com/en-US/hardware/xbox360/highdefdetails.htm

Oh right. I see. So the cable that came with his 360 premium will be the best cable he can get?

It comes with a component HD cable, however I find the VGA cable is a tad better.

linky.

depends on the tv

some tvs are better with component than with VGA or HDMI

Apparently in the Spring update the VGA output of the 360 will be improved again allowing colour levels to be adjusted over VGA.  This was a common issue as the VGA output had an issue with quite a few HDTVs because the image looked very washed out.  Something to do with voltage levels or something.  *shrug*