Heads up, you may not necessarily want L4D if you're getting L4D2. Squidthesid said valve was working on porting all L4D1 maps to L4D2. Although I don't know what his source is. It was suggested on the L4D blog that all map makers port their L4D1 maps to L4D2.
I have SC2 but would be willing to let it go for $25... I was really having trouble moving it, so I decided to ebay it (prices fetch for higher on ebay, like ~$35 or so according to past completed auctions, I guess because of the security?)
That said, since I have 2, happy to sell the key for 25 if you'd like. PM me and we can make it happen.
Since I literally JUST put the auction on ebay, if anybody else wants the second copy, let me know now, and I'll cancel the auction.
On the other hand, if anybody wants to try their luck w/ a 1-cent auction, some advertising never hurt ;)
Though it's going to completely out me from trading anything for a copy since he'll get both (sigh), you are able to gift a 4pack. You just have to do it through the website. Here's how:
Add the 4pack to cart, then navigate to this url: https://store.steampowered.com/checkout/?purchasetype=gift
You can then gift the 4pack to someone as a normal gift. They will get the first copy, and then have 3 spare. This does work. Source: Personal experience