Don't get hung up on getting the fastest SSD. Quoting Tom's best SSD for the money article.
http://www.tomshardware.com/reviews/ssd-review-benchmark,3139-6.html
" As a point of comparison, a file operation completes 85% faster on a low-end SSD than it does on a high-end hard drive, but there is only an 88% speed difference between a high-end hard drive and a high-end SSD. That why you shouldn't let less aggressive benchmark results at the low-end deter you from making the switch. You don't have to have the best SSD to get great performance relative to a hard drive. "
I have a tier 10 Vertex 2 I bought in late 2010. I see no reason at all to upgrade to the latest and the greatest when Windows still boots in under 15 seconds. I got it for overall system responsiveness and every click seems pretty much instant.
In fact, if anything I would go with a slower SSD with more capacity. Even with 120GB I still feel like I have to micromanage space. I have Windows 7 Ultimate x64, Office 2007 and other programs and about 10 games on here. I have to uninstall games I am not actively playing to have space for new ones. Easy enough with Steam but still.