Ah, I the love PokÈmon games- currently working on Diamond and Platinum. As for my ten favorite ones, other than my top favorite one, they are in an undecided order. I have ten favorites, I just haven't placed 2-9 in any order yet.
2-10:
Clefable
Mew
Smeargle
Palkia
Blissey
Latias
Jirachi
Porygon-Z
Shaymin (Land Forme)
1:
Missingno.
(Accident, glitch, etcetera, it is no less a PokÈmon than any other one in my opinion. They are still caught in a PokÈ Ball, they battle others, they have stats, and so forth.)
My favorites change periodically, so my top ten now most likely won't be my top ten later.