Hotmail, Yahoo, Gmail Attachment Size Limit
Email has allowed us to send files & documents online without any fees & it can reached the recipient in just a few seconds time. However there’s a drawback : Email service providers such as Hotmail, Yahoo and Gmail have attachment size limit for the files being attached.
So what are the attachment size limit?
Hotmail : 10MB
Yahoo : 20MB
Gmail : 20MB
So now you know which email service provider that you should choose 
If you are finding an alternative to send big size files, try service such as yousendit.com which allows users to send files up to 2GB!
This list is outdated, all 3 of these sites now have 25MB attachment limits
Right now all have 25 mb but when you attachment over 10 mb there very slow.