Apart from the TOP card, I'd say the Gigabyte one. Those two seem to be the main competitors when it comes to OC'ed 670's and which have performed pretty nicely. I believe MSI has come out with an OC'ed version of the 670. Definitely give that one a thought because MSI also makes pretty good quality stuff. Their Twin Frozr technology has proven to be very efficient in their past products. See their Twin FrozrIV version:
The EVGA FTW and EVGA SC versions were also out for some time, but I believe there was a product recall by EVGA in the series, so that might not be an option. Hence, I'd say either the MSI Twin Frozr or the Gigabyte Windforce. MSI would be my choice.
Alternatively, you could get the non-TOP version from Asus and OC it yourself.....'IF' you are comfortable with that!
The TOP version is not in stock where I want to buy it, but the normal one is. Du since Asus "handpicks" the cores that are overclocked without problems, wouldn't that limit the chances of getting a "good" core with the normal version?
Would have gotten the MSI version if it hadn't been for the fact that it isn't in norway yet, only the reference cooler.
I honestly don't know much about Asus 'handpicking' the cores. But even if that were the case, that would hold true only for the OC'ed cards (TOP version), not the non-TOP series. The non-TOP series would be at reference speeds/ settings only with aftermarket cooling. So I don't think that would limit the OC'ing capability of the non-top versions.
So yeah, I'd say the normal DUII card should be just fine even if you want to OC it yourself. Just make sure that you're OK with OC'ing and have the right hardware (PSU, etc). You can get help here with OC'ing the card if you want.
Oh, and the TOP version is pretty much out of stock the world over, not just Norway! Those babies sold out like hot cakes on a cold winter morning!