In what? For loading games and what not, probably the 10k rpm drive. Better seek time for loading all the small files. For copying large video files from that disk to another array, then it'd be the RAID 0 setup.
I finally upgraded my 7200 RPM drive to a 10,000 drive recently. The biggest difference on the 10000 RPM drives is that the seek times are cut almost in half. This decreases time when seeking for random files and such, great for booting OS, loading some games, and such. I opted to get a smaller (36 gig) 10000 RPM drive, and use my old 7200 RPM, for backup, and document space.
As far as benchmarks scores and such, my 10000 RPM drive scores much better, but then again, my WD 80 gig 7200, always scored pretty low for some reason.
When deciding between a 7200 RPM and 10k RPM (both non-Raid), there isn't a huge performance differance, so you have to decide the small performance gain is worth it. I was sort of on the fence about it, and finally said screw it, and bought one, I was impressed.