Coming into this one late.
So Half-Life 2 is pretty much my favourite game ever, at least until Episode 1 trumped it with better pacing and characterization.
Episode 2 is okay. It's good, but not great. I don't see myself replaying it 50 times like I did with Episode 1.
I got The Orange Box for the 360 because I'm still seriously thinking of getting rid of my un(der)used PC, but then I wanted to play Team Fortress 2 on the PC because it kinda sucks on the 360 (limited to 12 players realistically because of the peer-to-peer rather than peer-to-server architecture) but I'm all about replaying HL2 on the 360 now. They've changed it up a bit on the 360 and added some new effects and animations that really make it feel more intense. The camera moves a little differently, more jarring when something explodes or a zombie hits you, it really feels better now.
Love it.
And Portal is hilarious. The times where you have to jump off a cliff and shoot a portal in front of you which sends you flying horizontally into a wall where you have to quickly shoot another portal to land up above the ledge you started from? Well, this kind of shit is genius, although requires more Manual Dexterity than I often posses. Thankfully the save system is very forgiving.