My barely-a-year-old 360 took a dump the other day. Was working fine at one point, turned it off, turned it back on a few hours later for some RB2, got the E-74 error, out of the blue.
When I originally bought it at Best Buy last year, I bought a replacement plan along with it, so I boxed everything up and took it back to BB. They tested it out and let me exchange it for a new unit, so I picked up one of the new Arcades with the Jasper chip. Also got a new replacement plan. Best part was that they gave me the difference between the old unit ($350) and the new unit ($200), so I got a gift card for around $135, most of which I blew on Microsoft Points.
It sucks that my old one only lasted a year, and I am now missing the chrome disc tray, and I have to go through the rigmarole of transferring all my downloaded stuff over, but all in all, I'm pretty happy to have a Jasper. Plus, I got some free games out of the deal, too--the ones that come with the Arcade now.
To sum up, I guess I could say that I'm really glad that my 360 crapped out.