Now that the prices of SSDs are dropping I'd like to buy one for my boot drive, even though my mobo is SATA II so I won't get the full benefit of all that speed.
Currently, my system partition adds up to a bit under 64GB. That's Win 7 Pro x64 and all my applications. That also includes my paging file and an unnecessarily large Recycle Bin. Do you think I'll be fine with a 90GB SSD? I suppose 120GB would be even better, but there's a WAF to overcome.
I think you would be better off just saving for an additional month or two to get a 120GB.
And you also want to get a SATA III drive even though your motherboard is SATA II.
SATA III drives have newer firmware so they will last longer, maintain Read/Write speeds longer, and are generally more compatible/reliable with different systems.