I've got a few games on Steam that I've hit the activation limit for. You shouldn't have to deal with 3rd party DRM AND Steam - that just STEAMS me. If I could buy games on steam and not deal with 3rd party DRM I'b be happier. At least UBISOFT isnt limiting installs.
Another issue I have with steam is that some games aren't updated. For example Splinter Cell Double Agent - sure it was a mess but with the latest patches you can enabled HDR and AA and support for widescreen resolutions. However my copy through Steam isn't the latest and I can't enable HDR and AA nor does it support 1680!!?? WTF?? and if I try to install the latest patch it looks to install but when I run the game its still not patched up to the same as my retail copy...
and with Crysis on Steam they removed the whole 64 bit folder...nice
(I had bought it through Steam for a few bucks during a sale and wanted a copy on Steam)