I was taught how to sharpen a drill bit on a grinder in High School Metal Shop. While I'm no expert, it's pretty simple to get a decent edge on a bit in less then a minute if it's just getting dull and needing a touch up.
My current grinder is a small, half horse power, cheapy that has one fine wheel and a course wheel. The support in front of the fine wheel has a groove in it that is perfect for drill bits.
I received a Drill Doctor as a give way back when they first came out and they had commercial on for them all the time. I was impressed with it at first, but didn't think it was faster then my grinder. Then after using it a few times, I wasn't able to get the same results I did when it was brand new, and then it sat on my shelf for a few more years until I threw it away. I forgot I even had it until it was mentioned on here. Do they still sell them?