Best of both worlds? Sure, why not?
BTW, I know that Id traditionally has a rather small development team. Anybody know how many people were involved with HL2? Or how many people are at Valve in general?
It makes sense that HL2 seems to look like a better game at this point - I have the feeling (and the game looks like) they had more human resources to throw at the game than Id did. Maybe if Id hired more people, maybe Doom would be more impressive, but at this point, I'm of the opinion that they're apple and oranges. Doom1 and 2 didn't really have a story; HL 1 did. Doom was a pretty fast and furious, with wave after wave of monsters streaming on to the screen, while HL focused on a more slower-paced story-driven game.
I think each franchise is focusing on what they do best. From what I've seen from HL, there's some elements of puzzle solving (what weapon to use where and at what time), team work, and big battles over really large enviroments. Doom is more of a survival horror game in first-person which provides a pretty spooky, claustrophobic experience in really tight quarters with lots of scares and surprises. HL seems to have the more fashionable gameplay, at least as far as the future of FPS's go, while Doom 3 seems to be more traditional.
Which will be better? HL2 has the advantage I think, just 'cuz of it's more innovative game play (or at least the gameplay that the videos and reports are hinting at), but the Doom 3 experience has the potential to be an entirely entertaining experience in it's own right.
I'm with Rizz, I'm going to buy both.