For the record though, you don't get a banned account for cheating, only banned from that anticheat, really. Where theres a more apt problem is your account may be limited if you perform a charge back. However, charge backs aren't really ment for those who buy games, play them, and charge back. If you're not doing something extremely cheeky like this, you shouldn't really run into any real problems.
Now if valve goes bankrupt, or gets sold you have a problem. Being in Europe, I own my games, and I'll be totally justified in downloading them all and cracking them. However, it still is an issue, and is one of the reasons I tend not to pay full price for games. On the other hand, most big games are doing the online DRM thing and I believe EA has a habit of shutting down multiplay servers when they release a new version, so its more of a "i quit gaming" problem than a "I wont use valve" unless you prefer to stick with only humble bundles.
Either way, I personally feels valve is basically the only (or first, at least) DRM which justified itself in the market, and I'm happy with the sales / unlimited downloads trade off it offers. Nobody is forcing you to buy the games.
Edit: By the way, valve doesn't force you to use DRM (other than to download your game client). Many of the games work directly by launching the .exe, only some require steam verification to run. The reasons games use valve DRM is because the publisher / dev wants to use it, otherwise they don't need to. I'm more than happy with this DRM when you compare it to 3 x limited installs, rootkits, or always on drm competitors offer.