.NET and C# Coding
Developer Network - Microsoft's developers page, including
their excellent library of documentation for .NET, C#, VB, Internet and Office
Project - Some great utilities, applications and code
examples provided by users around the world that you can include or modify for
your own .NET and C#/C++ applications. Better than it's rival
Google Groups - C# - When you're really stuck on a development problem, try UseNet, now operated by Google Groups. Somebody usually has run into the same problem as you, and (sometimes) has the answer.
Web Design and Layout
Monkey - Some useful tips and tricks on client-side internet
World Wide Web
Consortium - Working group that sets and publishes technical
standards for the internet. Highly useful for getting the official word on
subjects like XHTML and
A List Apart - Some great articles on website style and design, particularly for CSS lovers like myself.
ColorMatch 5K - A simple but essential utility for getting the right colour combinations on your website design.
Use It - Web useability Guru Jakob Nielsen's website. Essential reading if you don't want your website visitors to murder you with frustration.