Case study: I am subscribed to a mailing list that only accepts .edu addresses. Gmail allows me to change my sender address to accomodate this. This system is broken, however, in that Gmail defaults to my gmail.com address even when someone sends a mail to my .edu address, so I constantly end up having my e-mails rejected when I reply.

If you have an alternate e-mail address, and someone sends an e-mail to that address instead of your gmail address, gmail should wisen up and make that your sender address for that e-mail. This has been bugging me forever!

Settings / Accounts /
When I receive a message sent to one of my addresses:
Reply from the same address the message was sent to

Interesting! I had that checked, so apparantly this feature doesn't always work...

http://daggle.com/060131-134544.html

The only time I've noticed the feature to work is if someone emails you directly and not as a hidden address behind a mailing list. At my uni for example, there are mailing lists for each year group, module, etc. If someone emails you through such a mailing list Google cannot detect whether the hidden address is "To: *gmail.com" or "To: *otherDomain.com".

It would be much better for Google to put the power in the users hands in my opinion and allow us to create some sort of Filter to allow us to default reply with another address in certain circumstances, like based on the sender and not the received address. If there is a powerful enough filter then it can allow us to tailorise it to our own circumstances.

<< Settings / Accounts /
When I receive a message sent to one of my addresses:
Reply from the same address the message was sent to >>

I have that set, it doesn't work, and as far as I know never has.