At least an 8 gig card and maybe a 502 partition
I have 16 gb and have a 2gb partition
And at least a class 4
Partition will give you extra space to put apps on your SD card
I saw somewhere that said it's either a class 2 or a class 4. Either way, the 2gig you got with the phone is as close to filler as they could get away with. I gave mine to my wife for her digital camera. I bought a 32gig from Microcenter in Chicago for $20. Class 10 even. Solid as anything, worth the money.