1) How long have you been collecting cels?

3 years! 

2) How much do you spend on cels per month? (Average)

erm.... $----.

3) What is your favorite cel? (Post pic)

its hard to pick one, but this Last Unicorn cel was the
biggest stroke of luck in my collecting so far. I have cels
I think look better, or were rarer in the anime... but this
is going back to childhood :)

4) Assuming you buy cels off the internet - what is your
   favorite site to buy them from (not necessarily where
   you buy cels most regularly)?

I dont like to pick favourites ^^;
And I dont have a favourite really, so many dealers have been
a great help over the years. I wouldnt recommend one over
another.

5a) Do you concentrate on specific characters or series or    both?

both!
Trigun - enemies
Gatchaman - everybody and everything 
Escaflowne - rare characters/folks I dont have 

 b) If you collect for a series, do you go through the 
    trouble of finding at least one cel per character?

no, I used to though.

6) Have you ever purchased a cel from EBay or Yahoo or some
   other auction site?

often! from ebay.

7) Do you have family members who also appreciate cels?

yes, in an "I dont understand it, but if you say they are
worth money, I'll get some too" way :)

8) Do you have friends who appreciate cels?

yes - most of them do!

9) In the space of this form box (i.e. the entire message
   cannot force scrolling either vertically or horizontally
   in the reply text box), please explain WHY you think 
   cels are so addicting - imagine you're trying to explain
   to someone why they're so great. ----------------

ACK. I doubt I am qualified to do this since I discourage
competition and I am also trying to cut down on my hobby  :)
I would say they are almost always guaranteed to be worth
more or just as much later on, unlike some gambles on the
stock market... :p And hey they look better too.
hows that?