This happened to every PC game that used Steamworks, and I would say that the launch of the first Steamworks game that started it all, Half-Life 2, was noticeably worse as Steam wasn't nearly as stable as it is now.
I'm sorry, this is not acceptable. First, as an avid Fallout Fan, I have been tracking the game and waiting for the New Vegas launch like Vengence, only now to find out that I need to launch through Steam to properly activate on the PC. Saying that it is "better" doesn't make it good, nor does that excuse the fact that I can not verify what is being downloaded through Steam and there was no word of this during the Launch. Maybe those who ordered through Steam had the notion, but I like to keep things a bit old school, so I got a copy of the disk. That should be all I need to play the game, end of discussion.
Seriously, Bethesda dropped the ball on this one. I call Fail. Next time you want to serve me one up the ... at least buy me dinner first.