One of the things I have learned these past few months while drinking freshly roasted coffee is how the size and consistency of the coffee ground can affect the brewing and taste of the coffee.
A Burr grinder uses a spinning metal plate to shred the coffee evenly. And Burr grinders have settings that allow you to adjust just how course or fine your beans are ground. For instance if you using a French Press or AeroPress you will want a coarser ground coffee. Whereas your traditional drip coffee maker you will want a medium ground coffee bean and for something like Turkish coffees you would want an extremely fine grind almost powder like.
I bought myself a Burr grinder to try out for myself the effect it would have on flavors and I instantly liked how consistent my coffee grinds were. It automatically knows how much coffee to grind up based on the amount of cups I want to make. (Of course that could vary as to how strong or weak you like your coffee.) And my kitchen smells amazing after I grind up the coffee. While the Burr grinder is a bit more expensive than the blade grinder it also is larger and takes up more counter space. You can store beans in the top of the grinder, but I only do this when I know I'm going to be using them daily and quickly. I really liked the quality of the ground and knowing I could easily adjust that for times when I use the drip coffee maker or the Aeropress.
Air is detrimental to coffee. For the best aroma and taste your coffee should be freshly ground before brewing. You will be amazed at the difference.
Also, it's a good idea to grind flavored coffees in a separate grinder than non flavored coffees as the oils in flavored coffee leave behind a residue that could alter the flavor of your coffees and the oils can build up over time on your blades and dull them. I personally use the blade grinder for all my flavored coffees and the burr grinder for my non-flavored.