It's not Valve refusing to sell it's the publisher. Makes no sense for Valve to not want to supply games in certain areas. Rockstar have spoken, no Max Payne 2 for you.

Yeah funny that. In this case Ubisoft had told them not to sell to the UK, (presumably when Avatar was released -- as that was the first affected game) but they continued to offer Arse Crap 2 until Ubisoft told them to stop again -- at least, that's the impression that the Ubisoft (un)official rep/forum moderator gave on Steam's Arse Crap 2 forum.

Judging by the insane amount of posts on any thread related to draconian DRM on this forum, I think I'll go out on a limb here and say DRM sucks.

Those people are the lunatic fringe that no one listens to. Most people even here praised EA when they announced their latest releases will only use SecuROM for a disc check. Generally people do not have any problem with the following DRM methods:
- SecuROM disc checks
- Steamworks
- GOO
- GFWL (if the limited activation bug is removed)
- Account based multi-player
- SecuROM that allows you to de-authorize a computer
People DO have a problem with the following DRM:
- Limited activations with no revoking tool (TAGES)
- Disc checks that can potentially damage your hardware (Starforce)
- Single player games that require constant internet connection (UbiDRM)
- DRM applied on top of other DRM (SecuROM/TAGES + Steamworks. GTA4)
- Regionally restricted activation (Steamworks + MW2 or Empire:TW)

Makes no sense for the publisher to not want to supply games in certain areas...

I agree and yet there it is. Activision, EA, Squeenix, Sega, Ubisoft and Atari all do it.

I disagree with this good sir.
Steam is much less invasive than most alternatives, especially considering Ubisoft's new DRM. Obviously having no DRM is the way to go, but Steam is the next best thing.

So, US release day is here, has anything hit the fan yet?

Dunno about the US release, being European, but so far I feel GameSpot's summary (intro, pros and cons and merits /demerits) of the game to be quite accurate: it's a great game, if you can get past the DRM. After I bought the game yesterday I couldn't log in or even create an account for hours, as servers seemed to be struggling and the Flash-based account creation interface kept crashing.
Haven't had any trouble playing the game at all since - checkpoints don't seem to be as frequent as advertised (I seemingly lost about ten minutes when I exited the game yesterday - although that may just have been the main quest's progress), but I've yet to be kicked from the game. Uplay needs to be better integrated, but that's about it. The only time I've gotten the "connection lost" message was when I switched back after alt-tabbing to connect to a remote network.

You are lucky you only bought it Yesterday Whitecroc as many more have had it refusing to work for longer. Last I checked they are expecting the servers to catch up 'soon'. If that means the attacks have magically stopped or they have simply plugged in more blades depends on who you believe really.
As for the US were are realistically going to have to wait another 4 hours to see if there will be another bomb blast over there.

Why another 4 hours? It's already 11:30 here, the game has officially been out for almost 12 hours now.

You really have to wait till everyone is home from school/work/whatever and the servers are facing the full stress.

I suppose, but since nearly every major retailer, most notably WalMart, broke the release early last night, we should have seen something already.

Well the amount of views the problem thread on the Ubi forums has certainly not slowed down. While checking for an answer for you the view count rose by 250 in less than 2 mins.