Okay, here's some random observations...first I'd like to reiterate what someone else said earlier - effectively you won't be able to resell your Steam-registered boxed edition of the game, and obviously there's no prospect of selling a downloaded copy. For me, and others I'm sure, that's a real knock. When I finish a SP game I pass it on to someone else to enjoy. I'm no longer using it but someone else can. Would you be happy to buy a car and not be allowed to sell it? Or what if you bought a DVD and couldn't lend it to a friend? If there's a system whereby I can pass my rights to a game on to another Steam user then 90% of my misgivings would be gone. I can't see that happening though. <shrug>
Intelligent bandwidth utilization? Sounds really cool. Currently I have 2 main PCs. One that's mainly for games and one that's mainly for the internet running Internet Connection Sharing. Any downloads are done on the old system and transferred over the lan to the new system when done. If I'm downloading a big demo I can leave one computer running while the other gets switched off until it's ready. I realise that's a pretty specific example and I can put in a router (in fact I already have a wireless rig I'm going to put in to run a connection for a Home Cinema PC next to my TV) but the burden of this intelligent bandwidth is shifted onto my main pc when running a Steam Enabled game. If I choose to not run auto-update with Steam in the background then I suffer when I have to patch to play the game. If I choose to let Steam beaver away in the background then everything else suffers. Say what you want about how unobtrusive it is but my main PC boots up with Systray and Explorer and no other programs running (aside from Windows system processes obviously - before someone challenges this) The more you have running in the background the more chance there is of something going wrong. Again, <shrug>
The system is going to foil pirates? I spend around a grand a year on MMOG subs and game purchases. I don't like piracy in general but you have to admire their ingenuity. Steam will not foil pirates, it'll encourage them. First the server activation will be removed, streamed patches will be released as standalone, there will be alternative master servers cropping up all over the world. The Steam system will be brought to it's knees by denial of service attacks, further encouraging legitimate users to use illegitimate servers. And you know what? Cheating will still be rampant and unstoppable.
Hey, on the plus side it kinda makes that $9.99 for a month of Steam, about enough to finish the SP game, look like a decent investment.