Hee Hee - I now have 50 invitations! And we now know for sure that they work from outside the US, and even outside the Americas!

A benefit I forgot to mention is that Gmail allows you a gigabyte of storage, so you'll probably never have to throw an email away if you don't want to.

Also, their spam filtering is very good - I've never had a "good" message end up in the spam box, or vice versa.