What gaming clients (like Steam) do you use?

Steam because of the sales... and Gaben

only steam, but sometimes origin for bf3

Steam and Origin because of BF3

Ummm... Steam?

Only Steam. I use GoG and Amazon, but neither of those require a client.

Steam. Origin only for bf3/dead space

There is nothing else but Steam. I have no idea what you are talking about.

Steam and Steam

Steam , Greenman and Gog.com but i guess that one doesn't count.

Steam, used Origin for three Hours to play BF 3, before i got tired of it.

For the most part, it's Steam for most games with Desura for indie titles for me... though thanks to HumbleBundle, Indie Royale and so on I usually end up with a copy in both accounts, and in that scenario it's the Steam one that gets installed.
I DO have an Origin account, but it is a terrible, buggy pile of horror and I do not enjoy using it.
I got a BeamDog account purely for the Baldur's Gate Enhanced Edition, but if it comes out elsewhere then I may uninstall it. No insult intended to BeamDog, it's just that the fewer accounts I have to deal with the better.
Does GOG's downloader count?

Steam and Origin, when playing BF 3 or ME 3

Steam, Uplay, Desura and Origin.

Steam, Desura and Origin.

Right now only Steam and Desura. I don't use Desura that much though.

Mostly Steam but also Origin and UPlay.
Also, GOG, but that's not much of a client but a downloader.

I usualy use Evolve to play with friends when can't set up a lan party,and the game has lan only.It tracks ingame time,it has full support on a hell lot of games,and you can chat with your friends while ingame,and has support for some of the IM out there,it's pretty cool.But i like steam too,so maybe that's why felt Evolve more like a natural followup of steam as an old games VPN client.
On the other side i really dislike Uplay

Steam, Uplay, and Origin

I'm mostly only using Steam but I also have Desura and Origin intalled. Altough, in Origin's case, I just use it to register my EA Steam titles on there as well for backup purpose. I've never actually installed or launched a game through there.

Only Steam.

Steam, Desura, Origin.

Steam and Desura here... ^_^

Steam and only Steam. I have not bothered with Desura yet. I might eventually get around to giving it a try for indie games that are not on steam yet.

I will never sign up for Origin. Unless they become fully independent from that scumgaming community of EA.

Steam and Origin.

I'll probably use Desura as well in the future.
I've only got one game on there and haven't bothered to install the client.