$45? You can get it boxed in the UK for $37 or $40 with DLC - as it's Steamworks, just have it delivered to a friend in the UK from simplygames.com ($37) or shopto.net ($40, DLC). International delivery from Shopto would still make it less than $45.

Alternatively, if you have the IGN discount at Gamersgate, it's $41 if you go through gamersgate.co.uk and you'll also get $2.31 back in store credit (easiest way is to buy 41,000 Blue Coins through your US account and make up the other 220 through reviews/ratings/profile setup if you don't have any already, and then do a Blue Coins purchase through the UK site).

Also, it's worth noting that Greenmangaming do not offer pre-orders - that's a pre-purchase. Given their history of problems with billing, security, checkout issues, key distribution and the recent reports on CheapAssGamer about people having GMG Steamworks games removed from their Steam libraries and EA and 2K claiming that GMG are not a legitimate reseller, it would take a far more significant discount for them to be attractive. ;)