You'll get faster speeds if you buy 2x 80GB drives and RAID0 them... but then, you'll get faster speeds yet if you buy 2x 160GB drives and RAID0 them. If you're buying these for a desktop machine, I seriously recommend you rethink your purpose. Buying them because they're shock resistant and generate no noise, or because you want to put it in a notebook are all reasonable reasons to buy an SSD. Buying SSDs for "speed" is a lousy reason to buy an SSD. If you just want speed, get 4x 1TB-1.5TB SATA drives. You'll get comparable throughput for a similar price, but more capacity and better reliability if you set it up as a RAID5 or something reasonably fault-proof. RAID them and do a benchmark to work out roughly how much of your RAID is optimal, then partition that section off and use it for your boot drive(s).
Not just this, but you'll be able to defragment them! People say fragmentation isn't an issue with SSDs, but I'm willing to bet none of them have actually owned an SSD or know a single thing about memory allocation! If you don't believe me you're welcome to see for yourself. Fragmentation is a challenge for everything, including RAM. That's why C programs (and Java, C#, C++, etc, etc) commonly use "[stacks]" for passing data between functions and managing automatically managed memory. Despite common beliefs, it's also one of the reasons why OSes don't offer direct access to RAM. They [page] it, which means the address an application receives is a virtual address and the physical memory may be non-contiguous at the lowest/kernels level (eg. the memory may be fragmented).