Glad you got your e mails back
This happened to me a month ago. I was travelling on the train and all of my e mails disappeared from my iPad and iPhone. Luckily I didn't have my Macbook Air with me at the time.
I contacted Apple who tried to initiate a recovery process. They managed to recover about a fifth of the e mails I lost. I had no explanation regarding what happened, and was simply told not to keep my e mails on their servers and to have a local copy instead.
Mobile me is not a cheap service, and quite frankly I expected more reliability. This experience has definitely taught me not to trust Apple with my music collection when they launch their iCloud service.
Thankfully, through the help of some macrumors forum posters, I was able to recover all of my e mails from my Macbook Air. I turned off my DSL router, opened the Macbook Air, archived everything, then turned the DSL service back on and popped everything back into mail.
I now make sure I have a local copy, which I renew every week or so