yeah, to those of you who had trouble transfering over the files from the old card, you need to make sure you show hidden files. If you don't see ~4 directories with a period at the front .folder1 .folder2, etc then you aren't seeing everything.
It should be about 2 gb if you copy everything off the stock card plus whatever else you have installed. If you just copy all of this over then you shouldn't need to "format" the card or anything beyond the formatting it shipped with.
For Mac users, search the web for somethink like "show hidden files mac OS X" you should get a lot of results with Terminal commands to do this, or find an Applescript that should toggle showing of hidden files for you.