I have a philosophical objection to requiring repeated internet access for a game that is completely offline, single player, and can be bought from an offline store and installed from a disk. It's absurd.
Also, I dislike not having control over patching (i.e, I like to have the individual patch files, so that I can install a game and patch it to the level that I need. Not some autopatcher that gives me the option of "no patches" or "all patches".)
It's overkill for DRM, too. Disk check is more than enough.
The only realistic reason that I've seen given for requiring Steam is that they want to guarantee that there's no used game market (since the game gets tied to your account).
Edit: and, as I've said, I use Steam and like it - for what it does well. But it's not the be-all, end-all answer to everything.
This. You've summed up my stance on Steam well. I'll also add that I use and like Steam very much, and I've got a large amount of games purchased through it. Just in the interest of fairness.
However, I also take issue to the patches, for two reasons. For starters, my old desktop computer was not very good. It
barely met the minimum requirements for Oblivion when it came out. While looking around, I came across the Oldblivion mod (for those who are not aware, it ran Oblivion without DX9 features, which would improve performance on older hardware). I installed it, and used it, and Oblivion was playable for a while. And then Shivering Isles came out. Suddenly Oldblivion was broken. It wouldn't work with the new patch. The developer stated that he had no timeframe for when it would be completed, and even now, he has not released Oldblivion for the latest Oblivion patch. While there is third-party support now, up until that time, if I had purchased Oblivion through Steam, and I had uninstalled Oblivion at all, when I re-installed it would be with the latest patch, which would break support with that mod, rendering it unplayable.
Sure, maybe I shouldn't have been playing it on an older computer then, but then I look to Dwarf Fortress. A game I have actually put off updating several times. This is mainly due to mod support (those who play DF can attest that mods like Dwarf Therapist are all but essential), but also major version changes (such as the move from the last 40d version to 0.31.25). I recall right after DF2010 came out, people were having big issues with it, and were actually going back to the previous version. If I were forced to use Steam's patching service, I would be out of luck the moment I hit update. I'd never be able to get a (more) stable version back, nor would I have a more familiar version to fall back on. Sure, the mod support eventually caught up, and its more stable now (anyone else remember dwarves melting in the rain?), but until I did update, I was quite happy running the previous version with mods that worked, and my dwarves not being killed due to a glitch.
EDIT: That being said, it is nice to see some of the misconceptions cleared up. Offline mode does exist, and I had to use it on my old desktop to play several games. But I didn't like having to haul my computer into my parents room to hook it up to the internet in order to activate Half-Life 2.