Do I need a vacuum coffee canister with a vacuum pump to keep coffee really fresh?

You are undoubtedly referring to something along the lines of the Vacu-Vin Coffee Saver Vacuum Storage Jar Set with Pump, described by specialty-coffee-advisor.com as "possibly the ultimate in coffee snobbery." This is basically an item that enables you to suck all the air out of the storage jar with a small pump, providing an extra level of protection from the elements. This may be a good idea, especially if you're storing ground coffee, as the exposure of so much of its surface area makes it that much more vulnerable to the elements. On the other hand, if you're really particular about your coffee, you're probably NOT storing ground coffee; you're waiting until the last possible moment to grind it.
 
Source(s):
Specialty Coffee Advisor: "Coffee Storage - Storing Your Coffee Beans Properly..."