New PC/No OS XP SP3 & Vista SP1

[animestan]

My pc
CPU Type: Intel Q9450
HDD Capacity: 500 GB
Memory : 4GB DDR2 800
Mainboard: Asus P5N-D
Video Card: Nvidia 9800GTX + 512M
Case: Antec Nine Hundred
Power Supply: ATX 600W

It does not come with a OS, i have both XP and Vista installation discs. I will be doing regular thigns like word processing, surfing, editing of videos and music and mostly gaming. Which OS is right for this pc? (and if its vista, do i go with 64 or 32 bit?)
Thanks

 

[chmod]

Go with Vista x64. That is what I use and love it.