I'm pretty new to DSLR photography, recently bought my first - Canon 450D. Bought a 2GB SD card for it and basically went for the cheapest as I thought "an SD card is an SD card - right?". After a busy session in my local park suddenly I was told the card wasn't formatted and lost all my hard work. Am I just unlucky or did I scrimp and now paying the price? If so, what brands are recommended?