I've ordered a Nikon D90 with UK dealer AJ Purdy, and they throw in two 4GB SD cards with the sale. How very nice of them, that's a good deal, I thought. And then I happened to look these cards up, and guess what they cost? Six pounds each!
Holy crap. I remember the first memory card I bought back in 2000. I think it was 64MB, and it was something like £170. Man, these things have dropped in a hurry! That's about 1/2000 of the price per MB in eight years.
I have stopped deleting pictures from the cards, I just fill them up and keep them as extra backup. That said, I haven't yet managed to fill up card recently!
By the way, unlike many gadgets, the Nikon camera is not spectacularly cheaper if bought in the US compared to the UK. Otherwise I might have ordered from Amazon USA. They will only ship to a US address, but I use a service I think TTL pointed me to originally, AccessUSA (MyUS.com). This service works great. They have lots of experience sending abroad with the least amount of cost and hassle with customs etc.