Advice about partitions for XP

I just got a new hdd with 640GB and I also have a 120GB. I've tinkered around with partitions in my last build, but I wanted to see what you guys are doing as far as separating multiple drives into partitions. I was thinking of setting up my new 640GB drive as my primary becuase it has a larger cache and would be dedicated to my programs and OS. The 120GB drive being dedicated to my data files (vids, music, pics, and setup files). And also not have to worry about it if my 640GB Primary goes bad or I decided to reformat everything. Also im not sure what logical partitions are intended for as well as extended partitions. Like always... appreciate your advice, thanks!

Have a read of this for information on Primary, Logical & Extended Partitions. I'd also suggest you put the paging file from XP onto the 120gb disk as this will speed up the performance of the PC.