Properly remove Exchange after migrating to Google Apps? Or leave it?

I've replaced Exchange 2007 with Google Apps, but now am facing the obtuse Exchange removal process. It seems that I need to go in and tear everything out manually (to uninstall I have to first remove the databases, to remove the database I have to first delete the mailboxes, shared address books, shared folders, etc) before uninstalling Exchange from the server, then I still have more work to do to clean Exchange out of AD.

This seems silly. Aside from general good hygiene, is there a compelling reason to uninstall Exchange properly rather than just wiping and repurposing the hardware?

I would personally take an image of the server to have a bootable copy just in case you need something at a later point then wipe it. Alternatively, take the drive out and store it somewhere, toss in another drive and enjoy a guiltless fresh installation.

In 2 years time when you've moved on to better things maybe, and no one either knows or can remember the details of what you've done now and where you left it at, someone's going to be really glad you finished the job properly and tidied up your AD and stopped them getting totally bizarre errors.

It's the professional thing to do, so its the smart thing to do.