I'd say no.
As almost a rule, Valve's games run better on the PC. not only that, but they seem to seriously neglect console gamers in terms of updates, etc.
The Half Life packs are fun for a play through, but if you're like me, you'll get bored. Portal has a little more power behind it, and I will come back to it every now and then, but I find it gets stale after multiple play-throughs. (It IS a puzzle game after all, with no changing aspects, and the dialogue/plot can only be surprising/clever so many times.)
Team Fortress 2 is fun, but I think it's awful on the 360. No updates, no attention, and not a very big community.