I cant wait. I played Half-Life, every add-on and most of the single player mods and still do a little Counter-Strike occasionally. I look forward, hopefully, to having a game that once again can sit on my hard drive for years as I play the sequels and mods during that time.
Im also happy with what I am seeing, especially Valves handling of the whole thing. The way they kept it quiet so its should seem like an announcement, followed by previews, followed by E3 showing, followed by a demo and finally release making the wait seem so short compared to many. Making sure the PC gamers get it first is great to hear. Not that I doubted they would, but you never know. For all the complaints we have for so many developers, hats off to Valve... so far