Don't get Half-Life it's HORRIBLE!! I've got it, hatedand I played it to see if it got better. It doesn't. The multi-player is awful, the singleplayer is never really fun, the controls are crap(the manaul aim sucks and the lock-on isn't a good solution tothe problem) NOTE: This is my opinion, you may like it as a lot of people apparently do.

The Red Faction games are way better.

If you're into flight sim/arcade games you should get Ace Combat: Sqaudron Leader and The Belkan War (flight games with a good story don't come around often)