Thought I should bump this up and give some rankings to the Private Practice characters (I know it isn't Grey's, but it's related given that it IS a spin-off). I think I dissed this show earlier on in the thread by calling it boring, but now that I've seen it, I actually really like it. It's not Grey's, but it's definitely not a bad show either. I basically like every character in this show, but I'm not going to do super long write-ups for them mainly because I am lazy, but here is how they would rank:

8. Naomi - She's pretty anal-retentive plus kind of immature at times (I mean, what kind of thirty-something gives people the silent treatment? Seriously.)
7. Dell - Dell is cute and likable, but he doesn't get as much screen time/development as everyone else.
6. Pete - At first, he seemed like a Mark-clone in that Addison liked him and he the fact that he has a similar charismatic but sleezy personality and the same man-whore tendencies, but as the show went on, he developed into his own character. I also like his specialty.
5. Charlotte - Wow, she's a bitch. But hilarious too!
4. Sam - A lot of people who watch this think Sam is boring, but I think he's a pretty good character. Really hot too!
3. Violet - Gotta' love a therapist who's almost as neurotic/messed-up as her patients!
2. Cooper - I love this dork!
1. Addison - duh.

I will continue with the couple ratings eventually! Lol.