LA Noire on PC has 3 layers of DRM.
1. Steam - people love Steam for organizing their games and automatically updating them. It doesn't do anything malicious or secret like SecuROM, but it is a type of DRM nonetheless (one with which people are okay).
2. Rockstar Social Club - more or less an annoying login service like Games for Windows Live. Requires an always on internet connection.
3. Gameshield - the real culprit. Scary thing is that there isn't much information about what it does. Machine/activation limits are unknown, as are any possible revoke/removal tools
http://steamdrm.flibitijibibo.com/the-big-drm-list/
I don't want to threadcrap. I have enough of a problem with having games tied to Steam (which is why I've only purchased a couple of games on there over a few years, and the rest have been activated through indie bundles). However, Steam doesn't screw with your hardware or hide anything.
SecuRom, Tages, SolidShield, Gameshield, etc. are the types of ridiculous software that are intrusive and extremely difficult to remove. I refuse to allow any of this stuff onto my computers. Even if it means I can't play awesome games, so be it. Not the end of the world.
(sorry for derailment, back to deals)