Today I got not one, but two gmail invites. Never rains but it pours, eh?
I've been saving all of my personal email since 1998, and I've only used 22MB. I'm sure that there are people who hit their 1GB limit, but under normal use, it'd take me quite a bit of time to do so. Maybe google's "never delete an email" push isn't that far from the truth.
Thus far, I find their conversation view to be very clever, useful, handy even. Other webmail services seem to me to be offering a poor man's IMAP. Gmail actually does something differently in a way that is useful.