A List Apart - Advanced DHTML and CSS based web design
CodeProject - Articles from everywhere covering MFC, C++, VB, .net and more
CodeStore - Domino techniques, articles, demos and more
Derek Reynolds - Brain Dump-o-matic - Derek's journal as he learns .NET, coming from a Domino background.
Dev Guru - Online references: Javascript, ASP, HTML, Perl and more.
Domino Error Log - Decipher Domino error messages - hosted by Codestore
Doug Ross - 75% Snark Free Journalism
Duffbert's Random Musings - My primary source for IT book reviews
HodgeBlog - Bunches of useful stuff from a system admin view point. And a Redwings fan. :-)
Lifehacker - Constant supply of useful ideas for life, technology and getting things done.
nsfTools - Advanced Domino Tips and Techniques
Peter Norvig - A bit more hard core CS (computer science) than most developers (code monkeys) tend to go for, but highly educational.
Random Fortification - My contribution to the spirit of DIY
Ruby Home - The official Ruby homepage, updated frequently.