Good comments from Retiredchief.
In the past, I used two Intel X25-M 80gb drives in raid-0. I wanted a single 160gb image. Benchmarks looked wonderful.
I replaced the two with a single 160gb drive, and could not tell the difference.
One reason is that larger ssd's have more nand chips which can be accessed in parallel. Sort of an internal raid-0.
As to which drive, I think you may have fewer issues with Intel, or, perhaps samsung.
Intel is supposed to be releasing it's 520 series drives to replace the 320 series soon. They have been offering some good rebates on the 320 series, and that should be a good deal.