Is RAID-0 faster with 10k rpm SATA or 7200 rpm SATA II?

I’m building a new high-end workstation; planning RAID-0 with either two 10k rpm SATA drives OR two 7200 rpm SATA II drives, but I don’t know which will drive types will perform best. PC needs to be super-fast for multi-tasking (MS Office & Internet research; MANY open windows).
Machine spec’s: Processesor is Pentium-D 930 (3.0Ghz, 2 x 2MB L2, 800mhz); RAM is 2G of 667mhz ECC DDR2 SDRAM; product is Dell Precision 380; HD options: 80G 10k rpm SATA w/8MB or 160G 7200 rpm NCQ SATA II w/8MB.