As promised, my long-winded Marvel villains "rant":

My fave Marvel villain, by far, is also one of my fave Marvel heroes - Wild Child.

After that, in no particular order, here are some of my fave Marvel villains:

Juggernaut
Garrison Kane
Sebastian Shaw
Terrax
Titania
General Clarke
Grim Reaper
Master Pandemonium (please don't call him Master Pandabear!)
Wrecking Crew
Norman Osborne, in any guise
Blob
The Zodiac Cartel
Crimson Dynamo
The Night Shift
Graviton
Master of the World
Morgan Le Fay
Scramble the Mixed-Up Man
"the scrambled eggs" - yes, THOSE eggs.
Puppet Master
Paste Pot Pete
Werewolf By Night (also on my heroes list)