Oddly enough, the same thing happened to me. I didn't forget my password though.
I had the original Half-Life. Shortly before the release of Half-Life 2, I decided to reinstall the original. I hoped online to grab the patch and discovered the new "Steam" thing. I registered my CD key in the system. Even after having installed the complete game from the disc, I found that I had to download the game image just to get the current patch. It was over 700 MB. I was using a dialup at the time. Yeah, forget it.
*Close Steam, Uninstall Half-Life, Run Unreal Tournament*
I hopped on Steam again last Friday for the first time in nearly 5 years because I heard about the free UTIII weekend. After an hour of downloading UTII was still at 5%.
I killed the download and started downloading the Half-Life still sitting in my game list. In less than an hour, I was up and playing Half-Life. Just took 5 years of waiting.
Technology has finally made it possible to download and play a 800 MB game in a reasonable amount of time. Maybe I'll check back in 5 years and see about 8 GB games like UTIII.
FWIW, I've also downloaded LotRO (~11 GB) in the recent past. That took about 9 hours but I let it run overnight. It wasn't a case of needing a quick gaming fix or having a time-limited trial clock running.
I have to say that my recent experience with Steam hasn't really done much to change my initial opinion. It's still a poor alternative to having a physical copy of the game. Rendering the actual physical copy to landfill material doesn't help the situation.
