So Many...What should I get?
First, strike Memory Stick and Memory Stick PRO from your list. Those are too big and won't fit inside your PSP.
Your best bet would be to get a Memory Stick PRO Duo. The high speed versions are only useful if you're transferring files via a separate card reader. Otherwise, if you're just using your PSP, it's doubtful you'd see a speed bump to justify the cost. Most people claim Sandisk memory sticks are faster than Sony. I haven't noticed this myself but seeing that Sandisk is also cheaper than Sony, I think that would make it the obvious choice.
__________________  -> still can't figure out why
Black US - 1.50
Black US - 1.50 -> 3.03 OE-A -> 3.40* LE v3
White JP - 2.00 -> 1.50 -> 3.03 OE-A
2 x Crisis Core JP - 3.60
Black US - 1.50 -> 3.40* LE v3
Black US - 3.03 -> 1.50 -> 3.40* LE v3 -> 3.52 M33-4 -> 3.71 M33-2 -> 3.71 M33-3
Black US - 3.40 OE-A -> 3.40* LE v3
Felicia Blue JP - 3.71 -> 3.71 M33-3
"Failure is not an option. It comes bundled with every Microsoft product." | 
So Many...What should I get?
Linear Mode
