Yep same thing here. I was having the 3 red light problem, indicating a hardware malfunction. I got my DHL box on Monday 11/28/05 and I sent it out the same day at 11:35am EST. I got it back today (12-2-05) at Noon. Well I got a "replacement" console instead of my old one.
I thought this was strange since customer service said that they would first attempt to fix the problem and return it to me within in 3-5 days. Well I guess they couldnt fix the system so they sent a replacement. My guess is that they are realizing that the problem cant be fixed or they wanted to be nice and not have me wait too long for my 360

Either way Im glad I got the the system back so soon.
Well, so far this "new" system has ran flawlessly. I can play all my games just fine without any freezing. Ive been playing for at least 3 hours straight since I got it back.
Overall Im pleased with MS. Only a few things Im concerned about...... where did this system come from??? Is it refurbished? Im guessing it is, since I doubt they have new 360's hanging around as replacements. Also if it is refurbished, was this an older system with simalar hardware problems as my old box? Only time will tell.....
Both of Our's must of been in the same batch. I also sent mine back on 11/28. This new console was made on 10/13 and has run perfect so far... MS has done a good job with this. I wonder how many back-up units are being held at Repair Centers? I thought this thing was in short supply, that's why I was shocked to see a brand new one at my door this morning.