Thinking about Mailbox and Message Size Limits

I'm a user, with perhaps a bit different perspective on this issue -- although Rudolf above fairly accurately conveyed a lot of the same points.  My organization recently implemented an 85 MB mailbox size limit, and I was identified as having the largest existing mailbox (about 160 MB at the time).  I used to reduce mailbox size periodically by saving large attachments I wanted to my file folder on the shared server.  I felt virtuous after doing so.  However, the same email announcing the 85 MB limit also stated that the shared server hard drive was essentially completely full so users also had to delete files from there -- and I was identified as the user with the larger data store on the shared drive.  The recommendation of our IT staff is to archive emails routinely to a .pst file on our C drive.  While this is fairly transparent while in the office (although I do have to search for emails in two places), this recommendation seems to fly in the face of why one stores things on servers: backup of files and access to them from more than the desktop in your office (such as from home, where I'm able to read office mail remotely).  Not only do desktop hard drives randomly fail, I've come back from vacations before to have my desktop machine replaced in an unannounced upgrade ("Oh, did you have files on that old machine?").

Sorry, but this capacity limit seems like a Microsoft problem to me.  I resent being made to feel like a "bad user" because I find it useful to keep old emails around as a reference, in a secure place I can access from home as well as my own desktop machine in my physical office.  Like Rudolf, I routinely need to dig up and cite emails from weeks or months ago.  Statements like the above, "Users should realize that a mailbox is not a file storage area," are as offputtingly scolding to end users as they are inaccurate (you're saying email is not an essential business tool?).  

In my situation, the 85 MB limit means I can have less than a month of old emails readily on hand.  In four days away from the office, without any emails sent my me, my Exchange store increased by 20 MB.  Many of these emails I could probably safely delete or archive -- but which ones?  I could spend (waste) 20 minutes or more each day on making choices/guesses about this matter, but frankly my ardor to work free overtime on worthy projects diminishes if the tyranny of mailbox size limits requires me to do regularly such a chore.  I will go home at 5 PM, which I doubt is the result my employer intends.  Immediately moving emails to the .pst file on my hard drive (as some "good users" in my office now do) leaves me half crippled when I log on from home -- or any place, if my hard drive fails.

As a user, I do compare the situation to my free Yahoo and GMail accounts, where I can have gigabytes of storage.  If they give that away with high reliability to millions of users, why can't my IT department with 80-100 users provide better service?