Yes! I’ve encountered the same problem, which I think is a bug. In 1.5.2, WordPress uses the “Name” and “E-mail” fields which visitors type in the comments to create the “From” field when sending to your email address.
HOWEVER, in 2.0, this seems to have changed. Let’s say you have a domain called “yourblogdomain.com”. The new “From” field used to send to your email address is now “[email protected]”. This would cause notification e-mails to bounce if you don’t have a catch-all email address, since this address DOES NOT exist.
If you do have a cpanel account, a temporary workaround would be to create an alias or forwarder called “[email protected]”. I don’t like this workaround though, since people who don’t have access to their cpanel won’t be able to do this.
Hopefully the WP developers take note of this.