Buy at least a 120GB, more if you can afford it. 60/64 is too small even if you call it a boot drive. 240GB would be nice for a few games as SSD's work best with 20% + free space
Don't get hung up on minor differences in maximum throughput, the biggest gain is from access times. I've a couple of M4's, four OCZ's and a sandisk ultra. I can't tell which one is in any system from the experience as a desktop user. The OS and motherboard make more difference to boot times than individual drive characteristics. I can say they are all awesome compared to spinning media.
Go for a decent brand, with a good reputation and look for a deal price.
I can't say a bad thing about any of my drives .... until one lets me down.
I picked a sandisk for the swimbo pc as they are rumoured to be solid on reliability and I wanted to spread the risk amongst brands.