GOG, impulse mostly.

GOG is the only digital distributor i use. i gave steam a try, but that was a year ago or something. i usually order my games via amazon or go directly to a local store nearby.

GoG, Steam and retail for newer games. Retail copies are cheaper than DD for new games most of the time

Strange, it works fine for me. I just tested it in Firefox 3.5, though I usually use Safari.

Yeah, that's usually when Gamersgate is slowest, too. When Hearts of Iron 3 launched (Paradox Interactive's new game, and they own GG) it actually briefly crashed at one point.

Play.com, mostly. Also, the local retail shops have a decent selection of PC games, so I have no difficulty finding new games (or bargain bins) locally. As for download sites, I have been using D2D a lot lately. Though obviously I only buy indie games or games that aren't easily available through retail channels from download sites. It's much cheaper and much more satisfying to buy proper boxed copies when possible.

Usually from Amazon or Sendit. If I am into old games, then GOG. And Steam, only for Valve games.

I usually buy games from GOG, Gamersgate, Big Lots, or Amazon. All the games tied to my steam account were gifts and I've never really trusted the service enough to spend my own money.

Not a bad site if you're looking for imports...
PlayAsia

I buy from:
GOG.com for classic PC games
Steam for Valve games and good deals (I swore not to pay full price again after their 50% sale on SF4)
Play-Asia for import games and accessories you can only find in Japan
CD-Universe for console games (Wii, DS)
Ebay for used console games
I also ask relatives and friends that travel to the US to buy games for me when they have the chance so I save on shipping.

GOG for old games.
Brick and mortar store for newer titles (I, too, want my boxes, discs and manuals).
Impulse and D2D only for games on sale, but I also only buy through them if it's something I don't really care that passionately about.
Bought one game through Steam to try the service. Don't like. I won't use it anymore.

I'm pretty much digital only. I use GOG, Steam, and Impulse. i tried Direct2Drive, but I don't think they have it quite right yet. I didn't have a horrible experience, but as a rather new PC gamer, I thought it was more difficult than the others. I will buy my kids box copies of 360 games, but I don't play them alot. I like the whole digital era. It's just really easy. I never read the manuals anyway.
I'll say this for GOG, I really think they do it very well. I just checked it out one day, and kind of got excited about old PC games. I didn't grow up playing any of these games. I really enjoy the site and the user reviews are great. I'd like a podcast. GOG should do a podcast about what games are popular and whatever else is going on.

I have my games on GOG, Steam, Gamersgate (only bought 1 cheap game to test the service), and D2D. I used to buy boxed games in brick and mortar store, but nowadays my collection is mostly digital...unless I spot some games in bargain bin for $5 or less. :P