I have Half Life 2, but have never played either Half Lifes. I actually have the Orange Box edition of HL2, which has the expansions. It was going to be my next, after Deus Ex is done.
You know, all these years later, Deus Ex still stands the test of time. I never get sick of it. System Shock 2 was a revelation this year. Never played it before, but LOVE it.
No fancy-pantsy Elven dagger-twirlers. Just tough guys.