On Windows the effect is rather limited as i see other people's benchmarks. A single 160GB is alot easier and you get TRIM which is way nice.
So in your situation, i feel a single 160GB would be a better idea; less trouble and with TRIM working.
In my situation, FreeBSD server with 5 SSDs, the performance scales very well. With 5x Intel X25-V 40GB SSDs i got ~1250MB/s random read performance; excellent RAID0 scaling; since the individual disks do 250MB/s max.