I noticed on amazon, the the higher up you go the higher the price, for example its cheaper to get two 16gb micro sd cards then to get one 32 gb. It's not much of a saving but I find that a little ironic because usually when you buy more at once its cheaper. But, I suppose its better technology or whatever to cram 32gb in there then it is to get 16 or less. I too use the 8gb c4 that came with th phone and am soon getting either 2 16gb or maybe 3 8gb, I don't mind the switching out of sd cards. And, although I do use the data on my sd card a lot, with flashing roms and backing up etc. I am still pleases with the speeds of a class 4.
Sent from my HTC Inspire 4G using XDA