Is somebody else in your group willing to take over DMing duties, part time? Simply having one other guy run a shadowrun or cyberpunk adventure once a month can be a great change of pace for everyone, especially the DM.
I find it really helps to put your campaign on hiatus every so often. It allows everyone, but especially the DM the chance to recharge their creative battery and try other things. I would definitely NOT end your campaign in some irrevocable way, because I can almost guarantee that six months from now you'll wish you hadn't.
And don't be afraid to try new systems. My group's been doing DnD pretty much since 3E was released at Gencon. And I'm alreadyplanning my next game using Hero System. d20 does certain things very well. But I miss fun martial arts and less work to run a campaign.
My group had a major break up wth personality conflicts as the main cause. I was already suffering from burn out but a lot of it had to do with the personality conflict going on. After taking less than a month off I started a new game in the same world but with a different line up of players. So far, it's been going okay with just some minor flares of players being goofy.
If I can get the goofiness over with we'll do much better.
I agree with not killing the game world and just taking a break from it. You'll probably want to go back with it later.
Keep your campaign going but move it to White Wolf's Ravenloft.
The player's will still be able to play the same characters but the genre will switch from fantasy to horror (if done correctly.)