Sample Producers

Precisionsound
Swedish sample-producer

Soundsonline
Home of EWQLSO, Stormdrum, RA etc

R.A.W
Herman Witkam offers some ethnic samples for free

Forums

Northern Sound Source Forums
Discussions about Gigasampler, Sample Collections etc.

V.I. Control
Sanctus Angelis Forum, Virtual Instruments & Sample Library Discussion

Soundsonline - Forums
EastWest samples forum

Composers

Todd K
Mikael Carlsson

Production Companies, Music Libraries etc.

First Call Music
Professional production music

Cinephonix
An International Network of composers

Sonic Librarian (also soniclibrarian.com)
Music library