RE: Do you prefer long or short anime series?
Depends entirely on how interesting the series and its characters can be, or at least if it can overall keep my attention for good reasons. Outlaw Star (duh) and DBZ -- the latter having over 10x as many episodes as the former in its original run -- are probably the best examples (in my case) of length not really being an important factor when it comes to what anime I'll watch. They kept my interest, so I kept watching.
"It turned out that the ghost was just Mr. Finley, who ran the amusement park. The spooky part is that, as soon as the ghost appeared, the teenagers' dog began to speak! And it spoke in a tortured parody of human speech: 'relp me, Raggy,' it would say. 'I am an abomination and rould re rilled. Rill re, Raggy.'"