*CSI Forensics offers a huge variety of stories ranging from G to NC-17 that are both het. and slash. It also cantains fics from all three CSI shows.
*Fingerprints is strictly a Gil/Nick slash fiction site. There are many wonderfully written storied on this page.
*Imagine is a site dedicated to Warrick/Nick slash fics with some Gil mixed in.
*What Makes the Desert Beautiful is a strictly Nick/Greg slash fiction site with many stories