I currently have converted 31 episodes of Pete and Pete to watch on it--and I can fit around 17 maximum at a time (so I'll likely put 10 on at once).
I also have the movie "Garden State", "Spinal Tap", and "Kill Bill" ready to be viewed (although I may not watch them on my PSP as I do not like the stretched resolution very much).
Finally, I have some episodes of Arrested Development, Starngers with Candy, and PeeWee's Playhouse ready to watch on the go. I can't wait to load these onto my 1 gig card