I had a vasectomy last April and I was mostly over it in 2 weeks. I still had occassional twitches of pain for about 3 months afterwards. After the three months, I don't feel any pain and you can't even see where the incisions were made.
I think that it is the best thing that I have ever had done. I can now go out and pick up girls and not have to worry about them getting pregnant. Granted, I can still get a disease, which I still use protection, but pregnancy worried me more than anything.
I say, if you don't want kids, or don't want anymore kids, then definitely get it done!