SATA I is backwards compatible with SATA II, and vice versa. But why are you getting an SATA I cable? Get SATA II.
It's not that I don't like Thermaltake, it's just that I don't normally recommend them for power supplies. And if I'm not mistakened, the Rosewill has more amps on it's +12v rails, which is more important. In my opinion, the Rosewill is better for the price. If you want, you can look at my Recommended PC Components
guide. But the final choice is your's, so go for the Thermaltake if you want.
You won't need anymore SATA cables, unless you're buying more hard drives, or optical drives. And the power supply should have all the power cables that you need.