Lol thats weird, Reghakr and I have just been chatting about the same thing..
I totally agree about modular, I use a modular system and it's fantastic as you plug in the cables you actually need.
If your gaming on a single card then anything from 500 to 650W should be ok. Dual cards and above need anything from 800 to 1000W..
So what type of system are you going for? Single or dual card?
Wow! Go Krypto Go!... I'm sure as long as you choose a well branded PSU you'll be fine.. You have to be careful regarding size with some 1000watters as the case can be a irregular size so watch for that..
no probs yeah i looked at the modstream when buying my 5770 but decided just to kill my Hiper typeR-580 before buying a new PSU and then just swap the inards over to the typr's case as i love the aircraft type connectors it has
I have the 530W version of your PSU and it's been a good little power supply. Unfortunately though it'll only give something like 36A on the 12v Rails combined. The 5870 needs at least 40A, hence the upgrade.