Too bad I already own the games. Every time I see that games I own are on sale for a really low price, I feel a need to buy the game, but I already have (bought it). Then I go and try to convince my friends to buy it cause it's such a good deal, but they never do (Except once, when I got my friend to buy TF2 when it was $10)
Now, two off topic things.
1) I LOVE these steam sales. I got Empire: Total War for $25, CoD WaW for $25, SF4 for $20, and Saints Row 2 for $7.50. I just love it when I've been saving up money for a game and then all of a sudden it's half off on steam.
2) I don't think that the original half-life has aged too horibly. Granted, it's no Modern Warfare 2 or other big, blockbuster FPS, but I still thouroughly enjoyed it. I was only able to play HL(1) recently because, well... I was only three when the game came out. Anyway, I don't think it has aged too bad. It may not be as innovative now as it was before, but it's still generaly fun.