experts-exchange.com - Paid but useful site for on demand technology help.

techrepublic.com - Mega site for all kinds of IT

UNIX, Linux

linuxcentral.com - The /root for Linux resources.

Sys Admin

samag.com - Useful if somewhat academic journal for UNIX/Linux

sage.org - The USENIX Special Interest Group for Sysadmins 

sun.com - Systems Administrator Resources and Community (by Sun)

Network Admin

networkworld.com - Site for the top network design and administration

nanog.org - North American Network Operators’ Group

Windows Vista Wiki Page

Paul Thurrott's SuperSite for Windows - Comprehensive information on Vista and other versions of Windows

Windows Vista Downloads

Windows Live Gallery - Site for uploading and downloading Web and Windows Sidebar gadgets

Windows Vista Utilities and Downloads - Additional software to enhance your Vista experience

Windows Marketplace - Shopping and download site dedicated to offering a broad selection of software and hardware for Windows PCs

Help and Tutorials

Windows Vista: Help and How-To
windowshelp.microsoft.com/ Microsoft's Vista Help site

Windows Vista from the How-To Geek - Top tips and tricks for Vista