CSI: The character background on both is pretty slim. Most of my info comes from the official site (http://www.cbs.com/primetime/csi/main.shtml), although the canon refutes Nick's listed-on-the-site alma mater, so it's not terribly reliable.

The big things we know about Nick: he was molested by a babysitter at age 9 and the only person he's ever told was Catherine (whatever); he's the youngest of seven kids, I believe; his father is a Texas Supreme Court Justice, and his mother is a public defender. He went to either Rice or Texas A&M, depending on whether you prefer season one canon or the web site info; he served as a cop on the Houston PD for three years before he transferred to the crime lab; he's big on football, video games, and geeky science stuff. He bought Catherine's daughter a chemistry set for her birthday one year (the same set that Grissom bought her).

Greg is, I believe, an only child. He grew up in San Fran, went to Berkeley and interned in the San Francisco crime lab for a couple years. He surfs and listens to Marilyn Manson and collects coins, thanks to his grandfather. He does use pet names in canon (baby, specifically) with his S.O., and he isn't shy about saying 'I love you'.

That's about all I can come up with off the top of my head. I don't know of any sites that do decent bios, but maybe somebody else does. This is me, not encouraging you to write an AU. At all.

HP Fic: I am so sorry. So, so sorry. I feel somehow responsible for dragging you into the big sci-fi vs. fantasy crossover from hell. I don't know what I got yet. Now I'm scared to check my e-mail.