Firstly - I currently have 2 HOWTOs both dealing with remote compilation and Visual Studio - if anyone wants to combine the 2 documents into 1, please go ahead.  I'll do it eventually, but eventually is a very long time in my world...

In no particular order...
Access pieces of hardware
<ul>
<li>HOWTO write to a GS register (priveleged/unpriveleged)</li>
<li>HOWTO read from GS mem</li>
<li>HOWTO create/compile/run a VU demo (can be adapted from my VU tutorials)</li>
<li>HOWTO combine VU code and C code (i.e. how to actually compile code using the EE with VU0/VU1)</li>
<li> </li>
<li> </li>
</ul>
Fancy functions
<ul>
<li>HOWTO speed up square roots</li>
<li>HOWTO swizzle textures on the cheap (The current Howto is just sparky's code from the forums, it doesn't explain what swizzling is, though some of hsfortuna's tutorials should help.)</li>
<li>HOWTO use MIPS/EE assembly (Myrkraverk, can I grab some of your info?)</li>
<li> </li>
<li> </li>
</ul>
Development environment kinda stuff
<ul>
<li>HOWTO cross compile using a Linux PC</li>
<li>HOWTO cross compile using a Windows/Cygwin PC</li>
<li>HOWTO setup samba</li>
<li>HOWTO allow access to telnet/ftp/other services</li>
<li>HOWTO setup the PS2 as an ftp/apache (web) server (I know for a fact this has been done - the HOWTO is just crying out to be written!)</li>
<li> </li>
<li> </li>
</ul>