Well if you're going to get 2 dx10 cards at any time, invest in the necessary size psu now. Only if you're sure though. If you only want to get one at all, get the enhance 5150gh. If you know you're getting 2, go with the silverstone zeus 850w. The x2connect is OK, but there are better psus out there (see: enhance 5150gh) for a similar price.
HSF: I can't remember, are you ocing a lot? If so, get the $35 scythe mine from newegg. It is easily in the top 5 (equal to ninja) hsf out there and pretty cheap too. If you are doing a moderate oc, go for the $21 freezer 7 pro from provantage. it is very similar in cooling performance but lags a little in dba (only like 3dba). Great value.
EDIT: Oh! RAM... that xms is great for ocing and is pretty much compatible w/ everything. Decent price too.