general
Apple : they make some great looking computers and software
Borland : creators of Delphi, Kylix and C++Builder
NaNoWriMo : The National Novel Writing Month is a once-a-year challenge to write a 50000 word novel
Non-Sequitur: very funny daily comic
Slashdot : a great news source for everything computer-related
The Register : another source for news, slightly more U.K.-biased
Tom's Hardware : reviews about all kinds of computer hardware
UserFriendly : great daily comics!

dsp
Music DSP archive : lot's of information and links, maintained by Bram De Jong
DSP Guide : abook all about dsp, completely online
TobyBear's site : this is a wonderful site. Really. So what are you still doing here reading ... go check it out!
VST source code archive : lots of example vst code to be found here

linux
Freshmeat : the place to be if you're looking for any Linux application or library
Kernel.org : if you want to compile a new kernel, this is where you should go. It doesn't only have all the kernels, but also some libraries you need to compile them.
KDE : really cool desktop environment for X Windows. I love version 3.0
Linux.org : do I even need to explain this one?
LinuxDocs : need help with any part of Linux? Try this website, there's a very good chance you'll find the information you need here
Linux on laptops : I found this site invaluable when I installed Linux on my laptop. A lot of very useful information covering just about any laptop out there I think
OpenOffice.org : the open-source version of StarOffice, available for Windows and Linux. Soon(ish) also MacOS X
RpmFind : this is a good place to visit if you're looking for rpm's (installable packages)
Sourceforge : home of many open source projects. It's a bit overwhelming

music
CoolEdit : very nice wave editor
Cubase : one of the best known sequencers out there, from one of THE music software companies. Generally a nice program, although it may be overkill for smaller projects. You can also find Steinberg's Wavelab wave editor there
FL Studio : this one is an obvious one, since I've done some of the work on it (most notably the plugin support). It's really a great program, for most kinds of music. Of course it's best suited for loop-based stuff, but since version 3.0 there's a piano roll, which allows more freedom. It got a 10/10 in Computer Music
Logic Audio : another well known sequencer. I personally like what they've done with the interface from version 4, but I haven't actually worked with it yet. Too bad they pulled support for the Windows version
Sonar : a new/improved version of Cakewalk, now at version 3
Soundforge : a great wave editor. It's the one I use when I've got waves to edit :-). And in version 5 there's now also MP3 support

programming
Delphi DirectX sdk : this is an sdk that allows you to create DirectX plugins in Delphi (much like the name suggests).
Delphi-Jedi : on this website dedicated to conversions of stuff from C/C++ to Pascal you'll find tons of translated sdks.

tools
Miranda IM : a very nice and light-weight icq client for Windows
mIRC : one of my favorite irc programs (the other one is KVirc in Linux). I recommend it if you spend any time chatting on irc
Total Commander : a very nice replacement for Windows Explorer. Personally I'm very used to the standard file manager in Windows, but I use this one for text file comparisons. I now also use this program instead of Windows Explorer, which for example allows you to treat archives (zip etc) as directories, do file comparisons, provides a commandline, ... And best of all, it was written in Delphi
WinZip : I think everyone uses or at least knows this one. I use it for .zip management