You said you like RPGs, so I would suggest a game I have called Blade Dancer, Lineage of Light. As soon as I get my homebrew going, I might sell it on Ebay. /grin
And speaking of Ebay, I got a 2gb Pro2Duo memory card for $27.99 if I remember correctly. The con about the memory card was I had to wait like 9 days for it to be shipped from Hong Kong. Some people say that the memory card is a fake but I don't care, it works for what I need it for. So far, I've saved games on it and also I've had movies on the card, and the movies have all played flawlessly.
And if you're into watching movies on your PSP, I would suggest you follow this link and learn how to convert your DVDs to MP4 format.
http://www.divx-digest.com/articles/dvdtopsp.html
You also need this to get the DVD file to your hard drive.