Reading some of the earlier posts, let's be clear: Steam is not DRM, Steam is a game launch client. Steamworks is Valve's DRM they've developed that developers are free to use, but they are not required to use. Many indie games, especially ones DRM free elsewhere (like here or Humble Bundle) do not include the Steamworks DRM even though you activate the game on Steam.
When I buy games from Steam I do make an effort to ensure I'm not buying anything with additional 3rd party DRM. I got burned recently when purchasing Bulletstorm on the summer sale, not realizing it still had GFWL and will most likely never be removed because the original developer is no more.
I'm generally OK with Steamworks as DRM because it's as consumer friendly as DRM can get. There are no activation limits, I can be offline without having to worry about constantly checking in to make sure I have a right to play the games, it doesn't destroy my optical drive drivers, if the game is available on multiple OSes (Windows, Mac, Linux) I get to play it on any of them without having to re-buy it (works out especially well for me with a prototype Steam Machine (I was one of the 300) running SteamOS, a tower dual booting Windows 7 and Linux Mint, a Mac Pro and a MacBook). The only real drawback is if Steam ever shuts down, the games may cease to function... but I tend to not worry too much about that because there are cracks for practically every game on the market, so if Steam shuts down, I'll just crack the games I bought. More than half the games in my Steam library were actually because of Humble Bundles though, so I have them DRM-free already, just in case.
Also almost every game I do buy from Steam is at steep discount. I never pre-order games or buy them during their "launch window". If I can pick it up for ~$5.00 or less in about 6-8 months then I'm usually ok with that. But again, preferably as long as it's not burdened by 3rd party DRM.
Some games I've avoided because of DRM:
Far Cry 3
Rayman Legends (probably just going to get this one on WiiU as it was originally intended)
Pretty much all the Assassin's Creeds (picked up AC1 here since it's DRM free)
GTA IV (which has the double whammy awful GFWL, and it's a terrible port)
Splintercell: Blacklist (actually got this for free with my video card but it requires Uplay. Nope.)
mqstout: Well, Steam (and, for the most part, DRM in video games) debuted with HL2.
Uh, no.
Steam was out for about a year before HL2 was released. HL2 was notable for being the first game that required Steam, even the retail disc was activated on Steam.
And hell no, Steam nor HL2 did not come anywhere close to debuting DRM in video games. I couldn't tell you which was the first DRMed game, but I remember plenty of them from the 90's, well before HL2 or Steam even existed.
AnimalMother117: Does anyone know if the Star Wars games: Dark Forces II:Jedi Knight, Jedi Outcast, Republic Commando, or the KOTOR games work well on Windows 7?
There's always DOSbox and VirtualBox or VMWare Player (and a copy of XP or 98) for running games that may not run in Windows 7, even with compatibility modes.
Magnitus: But basically, you can't have a digital DRM-free installer then right?
You might check the Humble Store, I know they had a bundle a few months ago with most of the X games which I'm pretty sure were DRM free but also came with Steam keys if you wanted to activated them on Steam as well.