We were promised a paperless office in the 1970's first and every decade since, but it's still just as far away as ever.  PDF's are great and the fax is nearly obsolete, but the average office still can't help churning out piles of printed paper.  So if we must have these purveyors of tattooed dead tree slices in the office, let's make some sensible policy decisions : 

Where possible, resist the demands for individual personal printers.  They've become somewhat of an executive status symbol, and while some may be justified most are not.  The well worn excuse of confidential correspondence can be nullified by ensuring your workgroup printer provides the functionality to store jobs with PIN protection, or purchasing an add-on such as HP's EIO hard disk to provide it.

If possible a single vendor makes stocking replacement toner / ink / maintenance kits both cheaper and easier.  If your requirements for large format, or industry specific printing requirements make this impossible, the odd exception is fine.

The most common support call from a user is that a document isn't printing because they've got the wrong paper size set.  The second most common support call is for replacement toner.  If you can teach your users to solve these 2 problems themselves, you support calls will drop by a substantial amount.  Until someones desides pushing harder is the way to resolve the fact that the only toner replacement to hand isn't for their printer model!