If you use Google Mail (aka Gmail) as your email service you'll find that you can now send and receive attachments as large as 20MB. Ever since Google Mail launched with 1GB of storage space, the maximum attachment size was 10MB, but this has now been doubled.
Unfortunately though, as most other webmail clients don't come close to matching Google Mail's current 2.9GB of storage space, there are very few email accounts besides Google Mail ones which would be able to receive such large attachments.
Google Mail has been criticised in the past for not handling attachments very well. Some users find that they have difficulty uploading attachments onto the Google Mail server, the system can be a touch unreliable at times. Unfortunately, there's no indication that any of these bugs have been fixed.
We've only got the Google Mail Help Centre page which confirms the increased attachment limit.