Good DIY suggestions?

Decware in Illinoise for low power amps and Hi-eff speakers. I built the integrated and it's a good product. decware.com
vkmusic.ca in Canada for Elekit amps. I built the TU-879 integrated, he (Victor Kung) also has a 300b integrated and is taking pre orders on a 2A3 integrated. Good stuff.
Tube Audio Lab in California tubeaudiolab.com has pseudo kits - He (Min Yang) will make the case, gather the parts, and send you a package with everything including decent instructions. I made a 2A3 amp. Top shelf stuff.

Good suggestons Sebrof. You could look into Bottlehead stuff too. Also, I have a set of DIY audio 300b monoblock kits that I've never put together (called Billie, I think) that I'd be willing to sell for a good price. I may get around to building them someday.

Wilmslow Audio in England has some very good speaker kits, DIY versions of ATC and several others. Madisound over here has some good ones also.

http://www.diyaudio.com

http://www.hagtech.com/

Audio Sector
Decware

www.audionotekits.com

Check Audiocircle. They have a healthy DIY contingent there.

http://www.zaphaudio.com

http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
are some good diy speaker links.

tubelab.com

gr-research.com

kandkaudio.com