I’m not going to make a habit of announcing these, but this one is just too big to pass up a comment on.
As you may or may not know, for a while now Steam have been running weekend deals, wherein each weekend they will offer a game (or sometimes a game bundle) at an extreme discount (usually over 50% off). Obviously, if you’re even remotely interested in the game being offered, these deals are hard to pass up.
The only conceivable reason I can think of for someone to not immediately buy that (assuming of course that you didn’t miss the sale) is if you’ve already got it. Portal alone is definitely worth it, let alone all that Half-Life goodness.
(Why are you still here?)