Why? WIN7 shouldn't take up more than 16 or so gigs, then you have your page-file/virtual memory.. You can have all your productivity programs on top of that and a few games and still have some space left over.
If cost is no problem then of course get all the space you have, but if all you got is a c-note on you, then go with a 60-64 gig.
Personally, I've been impressed with Mushkin's Chronos and Callisto series SSDs, as well as their RAM. Remember though that quite a few of the components that go into SSD production come from single manufacturers (like just about everything else!). As an example, my Enterprise-Level Seagate Constellations use Foxconn SATA controllers!
So don't get all twisted over reliability or performance. You could go with the cheapest drive on Newegg, and you'll probably not notice any performance or reliability difference.
Same size, for the 15 quid diff, I'd go with the Intel 520.
I have two 128 gig agility III. Only recommend them to my Enemies - LOLs
Performs almost as well on a sata II port as it does on a sata III, inwhich case the Sata II samsung 430 would be a better choice.
On size. While the 60/64 gig is the MIN size, the recommended size is 80 -> 128 gig.
You must remember that a 60 gig SSD is really only about 50 gigs ( base 10 vs base 2 loss (about 4 gigs) and Must leave at least 10%->15% unused another 6 to 7 gigs loss). A typical installation will soon eat up 30 -> 40 gigs excluding games and using the standard tweaks for maximizing space; Like, Disabling hibernation, stetting min/max of page file to same LOW value and/or moving the page file to HDD, and limiting restore points, and setting My Docs and temp files to the HDD. Bottom line is Yes it's doable, just have to keep close tabs on it and direct some of your software to install on the HDD. Remember what is NOT on the SSD will NOT be speeded up.