GMail

I've just started migrating my old mail to gmail with mutt through imap access

According to goglified about gmail space
1. 2912MB by October 11, 2007 midnight Google time
2. 4.2GB by November 23, 2007
3. 6GB by January 4th, 2008
4. 42GB by the year of 2038

You can read more about gmail storage