It Should be coming tomorrow!!!!!

Question is - what do I do when it arrives? (apart from plug it in...... I think someones going to do that for me though.....)
Some serious questions though....
Should I make a backup to DVD before I put a partition in or after?? (I havent ever made a partition before)
With 2 120Gb Disks how should I split it up?
I was thinking Disk 1:
20Gb P't for OS
Rest for stored music and Video editing files
Disk 2:
40Gb P't for games
40Gb P't for downloads and files
40Gb P't for Misc programs utilities
Does that sound alright? Or is that too many partitions?
And possibly the most important...
Do I install FS:ACOF or CFS3 first?



...!
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) as I had heard that a partition can increase performance or at least prevent deteriation of performance. It says "Create, resize, copy, move, convert, split and merge partitions safely" we shall see!
Mainboard: Asus P5K-Premium, CPU=Intel E6850 @ x8x450fsb 3.6ghz, RAM: 4gb PC8500 Team Dark, Video: NV8800GT, HDD: 2x1Tb Samsung F3 RAID-0 + 1Tb F3, PSU: Antec 550 Basiq, OS: Win7x64, Display: 24&