MSDN and its blogs are pretty exemplary, if a little slow to load and search (although there is now Google's Microsoft search
http://www.google.com/microsoft.html).
Blogs and articles I tend to stumble upon (which reminds me, it's a while since I used stumbleupon).
I tend to flit every day from one site to another, as there are not many development related sites that stand out as particularly brilliant all the time. However, there are a few that I come back to quite regularly, mostly links pages eg.
http://del.icio.us/popular/
not strictly programming, but mostly populated by geeks, and there are always the development related tags you can search on
http://www.dzone.com/
for articles/blogs of interest to developers
http://www.mostinspired.com/
gives a snapshot on current trends in web design
http://www.devlisting.com/
various web links
http://www.shellcity.net/index.php
freeware and links for hackers
http://www.bugmenot.com/
to get access to (free) sites/articles that want me to register
http://thedailywtf.com/
of course.
Web 2 Bull**** Generator
to remind me to not get carried away with all the latest hype in the development world
this is quite brilliant, very original idea, poetry and code:
http://www.haikode.com/
I spend a lot of time on wikipedia, eg.
http://en.wikipedia.org/wiki/Anti-pattern
And of course, the most important development resource of them all...
http://www.google.com