Just when I was starting to like the Steam way of buying games, it's started to wind me up with the download process. I bought STALKER on Sunday evening, and left my machine on overnight and throughout the day expecting to be able to play it when I got home from work on Monday. Alas, it has hardly downloaded anything, traffic graphs show it did a bit overnight and then stopped early morning. Repeat for Monday evening, and throughout Tuesday. Still not done. I've just been monitoring it while doing some browsing and it seems I need to keep a constant check on it and keep pausing/resuming to get it to download. Sometimes restarting Steam will get it going as well. It's now sitting on 99% with "10 seconds remaining" and it just won't download the rest of it. I could have got a disc in the post by now. Is it just me or has anyone else had the same problem? I'm sure it used to be fine, as I remember playing Portal/TF2 only a few hours after I bought them.
I bought Arx fatalis a few weeks back and had similar problems. It stopped a few times during the download, and mostly would restart if I hit the verify integrity button (it would stop trying to download in order to check the files, then usually restart and get a bit more done) I think it hit 99% complete and stopped for me too and I recall it took extra measures to get it done, but I can't remember quite what I did now, though I do remember that whatever I did, it instantly completed when I did it, which hinted it perhaps wasn't the downloading but perhaps the installing that was having a problem that time.
They had 150 kb+ speeds for me when I was downloading Half-Life 2... My only suggestion would be try to redownload it, but I'm not really sure that will help. In any case, bring it up with Valve I say.
I had the same issue recently. What cured it for me (at least as a workaround) was to double-click the game in the 'my games' list, which forced Steam to open the window showing the progress bar for the download with the checkbox option to "Launch as soon as the game is ready" etc. Keeping that progress dialog open maintained the download for me, while closing it would halt the download (though still claiming that it was downloading).
8 hours! Ha, it's much faster than that mate. I finished installing all the HL series, CS:S, D&D:S, TF2 and portal in < 3 hours the other day.
Should be an option in there somewhere to manually switch which content server you are connected to. That usually fixes things for me.
it took me about an hour and a half to get onto team fortress 2 on monday, it kept saying 'steam servers are busy, try again later'. May have had something to do with badlands coming out