Lots of info about Compact Flash here:
http://www.robgalbraith.com/
Look in the CF database.
I have a 512Mb LexarMedia 40xPro (or rather I don't, 'cos Mrs A's gone off to India with it in her A60). It came complete with a USB reader which is useful and wasn't an awful lot more expensive than the cheapo brands.
Par examplement:
http://www.dabs.com/38LT