KiNgBrAdLeY7: Too late. But better late than never... When you buy a game that requires Steam...
1) You do not buy the game itself, or its files.
2) You buy ONLY the LICENSE to USE it (much like a renting service).
3) You NEED steam to install it (even if only to start or finish the installation), to play it, etc.
4) Your product is VULNERABLE to enforced REMOVAL OF ALREADY EXISTING GAME CONTENT, WITHOUT WARNING or COMPENSATION, even if you PURCHASED the game WHOLE quite some time ago, much like the latest GTA Vice City and San Andreas cases.
5) Games that already come with DRΜ measures, are twice the pain to deal with, while using them on steam.
6) Steam keeps track of your activities constantly while you on it, like the hours played. It also collects data dealing with your tastes and preferences, so it can advertize to you "recommended" items to buy. Something that when generic webpages do to your system, leads them to your black list (or your antispyware's/antivirus').
7) You do not have direct control over your saved game content, because it uses a cloud to store them. The procedure to start a game anew by deleting your saves, if and when desired, is quite a pain.
You also run certain risks. Like when you use a code activation of a game, it is already used/redeemed by another account. Case in which, you have to return the product to the place you bought it, and struggle to have it changed, or if you aggressive enough, to get a refund. Steam support washes its hands of any responsibility and doesn't help, not even by telling you WHICH account "stole" it from you.
Also, steam support is quite chaotic; i once asked them for help, and they ridiculously demanded that i contact the company whose game i needed support on. Thankfully, i found an article that solved my issue, and guess what, the solution needed only some tampering from the steam environment. Those people do not even know their damn job.
Be careful when buying from steam. Think of it as encouraging the further trampling of DRM-Free titles. Last but not least, a great deal of games sold here, DRM-Free, suddenly were removed from our store, and either appeared on steam, or existed there already. Don't support the monopolies, and the bashing of the excellent, DRM-Free service.
Everything you said is true but Steam fanboys don't want to hear it. Five minutes of googling can back up everything you've said. And how come there are so many Steam fanboys hanging out at the GOG forum?