I decided that this comment response was probably too long to leave in the comments section. Plus, this way, it makes it seem like new content! (Warning: this will be even less interesting to you if you didn't care about my last post on user accounts.)
"There is a lot of development that you just can't do without an administrative account..."
I was specifically thinking about developing software that requires administrative access to run, which in the grand scheme of things isn't really that much, I guess, but includes some things like shell extensions, system services, drivers, setup programs, and so forth. You can't really develop something that requires admin access to run without being an admin. Some of those things could have been architected in such a way that they didn't need administrative access, most notably shell extensions. The decision to make working with shell extensions require admin powers was a decision that made a lot of sense a decade ago, and is somewhat questionable but not crazy today. There's also the case of developing shared system files—you don't need administrative access to build them, but you're eventually going to need it to test things outside of your sandbox. Of course, shared system files are getting a little passé, and that's a whole different topic. Anyway...
So there are a couple reasons that development tools might require an administrative account, but as you say, in general, they shouldn't, and it sucks that VS does. As far as I can tell, this has been changed for Visual Studio 2005, and you can now do all of your "normal" development with a limited user account. It's not something that really had a lot of user requests until recently; developers usually owned (either literally or figuratively) their boxes, and they're the kind of people who wanted full control. Even when it's no longer "necessary" to be an admin to use Visual Studio, I still think a lot of people are going to do it. I always run as admin. Out of the five computers I really ever use, I run as an administrator on each one. Running as an administrator gives me maximum power with minimum hassle, and at home, I basically don't have a choice, because I want to run games.
Overall, this is still an area where Microsoft as a whole is doing better than the average—but the Windows team is certainly not helping to increase that average. I still think they are going to have to make it annoying enough to use software that requires admin access and shouldn't such that people who write that software are compelled to do things right. I guess that's kind of like hurting the user in the short run (because I never had to type my admin password to run WoW on XP, but now I do on Longhorn?) to help them in the long run (so that Blizzard will make sure that WoW II doesn't require admin rights).