Seems that Exchange still is limited to 75 GB server store:
http://www.intelliadmin.com/blog/2007/08/increase-exchange-2003-maximum-message.html
Compare that to other server side stores limits:
I think I will go with the one that is able to grow to 256 terabytes!
Assuming I ever get my hands on that much disk (ha).
Also: don't forget to enable circular logging or Exchange will eat all your disk space!
Right click properties on "First Storage Group" of the victim server and check the circular logging. - Oh, and of course restart Exchange cause the settings don't mean much on the fly - of course Citadel reads changes on the fly, but that is that inferior free software and we can't expect the paid stuff to keep up :-)
http://support.microsoft.com/kb/258470/
And since links break, here is how to clean up space with circular logging turned off... Just make sure you have a good full backup daily. Everyone has a good full backup daily, don't we?: http://support.microsoft.com/kb/912375