Oh what the heck...I'll play along.  Besides, 
it's unnerving to see the forum this empty. O_o

Most collected:  Hmmm...this is kinda difficult 
to measure. Without a doubt: Dragon Ball, 
Sailormoon, and Tenchi.  Fushigi Yugi, Cardcaptor 
Sakura, and Slayers are probably up there too. 

How about a list of series that would be most 
collected if they weren't so expensive/limited: 
Last Unicorn, Mononoke, Lodoss OVA, Evangelion, 
Cowboy Bebop, Oh My Goddess!...

Cute/Cheap Series:  For me this was Tenshi Ni 
Narumon. Although, I started collecting because I 
truly love the series, not just because the 
characters are cute and the cels were cheap. As a 
whole, the cels are still cheap, but the really 
nice shots of popular characters/moments can get 
pretty expensive.

What do I look for in cels: I always admire 
people who have specific wish lists.  It's not so 
easy for me. I usually have a vague notion, but I 
rarely seek out cels from particular moments in a 
series. Sometimes I don't know a cel is a 
wishlist cel until I see it on a dealer site or 
on auction! ^_^; I'm usually attracted to near 
centered portrait cels where the character has 
open eyes and an interesting expression. Because 
of this, I basically just keep a small list of 
characters that I'm looking for. And I will 
almost never list cels that I know that I 
couldn't possibly afford.  I know what I'm 
willing to spend, so I try to keep it within 
those parameters.

Hope that satisfied your curiousity a little!

--rg