Thoughts on Mash ups

Warning - I think every video below is NSFW.
Mash-ups seem to go horribly, horribly wrong a good 90% of the time. It's a statistic (that I made up) I try to keep in mind while trolling the internet for mash-ups because despite the frequent horror shows out there I do enjoy a good mash-up. I've posted about Girl Talk several times and I'm pretty sure I've said before that I don't consider what he does a "mash-up", he is creating music with found sounds. So for this discussion, Girl Talk in all his danceable brilliance is out.
How many times have I thought, "I love Jane's Addiction and M.I.A., this will be an awesome song!" only to be subjected to a poorly synced, roughly mixed piece of crap. There is no set rule to follow when you are looking for mash-ups. Two bands that don't sound anything alike from completely different genres can mash up into something amazing as can two bands from the same genre and time period. A large part of a good mash-up is the masher knowing what he or she is doing. Apparently technologie has made it much to easy for just about anyone to mash-up anything they like and making it sound like they actually hate the mashees.

My biggest problem with most mash-ups, even the good ones, is that they are fun to listen to once or twice but they lose their shine pretty quickly. The whole novelty of hearing Madonna sing on top of a prodigy song is mind blowing the first time but not so much the next. But there are some mash-ups that have held my attention for quite awhile.
Everyone remembers when Danger Mouse mashed the Beatles White Album with Jay-Z's black album. The entire Grey album was pretty amazing. One of the standout tracks Was 99 problems mashed with helter skelter. It seems like just after that a ton of people took a crack at 99 problems and the best by far was DJ Tim G who did a flawless mash of 99 Problems and Jimi Hendrix. I've been listening to it for years, you can check it here.
Another mash-up that I listen to regularly is a Monkees/Iron Maiden mix. Check out the awesome performance video below.

All that having been said, I have been obsessed with Wugazi for the last couple of weeks. Wu-tang Clan and Fugazi mashed-up? Yes please. Check out my favorite track from the album 13 Chambers(yes that is 13 Songs by Fugazi mashed with 36 Chambers), Forensic Shimmy. Added Bonus, the video is made up of old kung fu clips, I think the Wu would approve.

Anyone know of a great Mash-up I should listen to?