Lol, to me:
<12 episodes = very short
12-16 episodes = short
16-30 episodes = medium
30-60 episodes = long
60-100 episodes = very long
100-200 episodes = excessively long
>200 episodes = insanely long

...


I tend to watch things less than 30 episodes long - don't have the time.  If you can sit around and watch all day (like you've mentioned), the longer ones probably suit better.
I prefer things short and concise, rather than longish stories that drag on and on through sideplots...
Having said that, I rated Full Moon (52 episodes) quite well... >_>

Interesting reviews, though I'd probably disagree with a few :P