Donald Norman's site on usability and interaction. Author of "The Design of Everyday things"

Usability website from Bruce Tognazzini (Apple's former Human Interface Evangelist)

Like a grown-up slashdot.

Genius

Its the new Rolling Stone don't you know.

Blog of New York web-designer Jason Kottke. One of the first blogs and marginally less masturbatory than the rest.

Consistently perceptive and intelligent blog from Zimran Ahmed.

Information Architecture site from Christina Wodtke et. al. Good, practical stuff.

Increasingly pompous, but his early articles on how to run a software company are bang on the money.