XP SP2 RC1 = 273 MB. I'm on DIAL-UP (usually around 5 KB/sec). I'm not touching that until it's final - even then, I'll probably order a CD, it would take less time to ship the stupid thing than to download it.

I did read a lot about that new XP firewall though - I think it's not going to help too many people, they'll just shut it off because it's "too annoying" (like people will do for antivirus software..) Those that actually care about a firewall probably already have one.