That is a pretty good deal. I might have to buy that now heh. I don't know though. I will be getting Wow this weekend most likely so i don't know if i should also get hl2 (since mmorpgs take up so much time).
Yes, you should definitely pick it up, it's a very good game!
Besides, if it's anything like the original Half-Life, the price won't go down for quite a while.