For the backup question...if you are using Windows XP, then use the transfer option in windows. Something like...windows transfer, profile transfer or something. It actually works very well as a backup procedure.
As for SP2...I like it. All of my online games are working perfectly, my server is easier to configuration for online gaming and I have to say I think my 'net connection actually got faster or should I say the bandwidth was increased. Not by very much but at least by 80-100kbps, jumping up to 1150 from 1050. SP2 is good and very easy to use.