My most "popular model" is a model I made a while back; a low-poly large beanbag chair, that I don't even think I did a very good job on : with around 400 views and 330 downloads a week. 8 people have added it in their collections, and it has 55 ratings. HOW!??! it has to be my least detailed model, easiest model(done in like 10 minutes), and doesn't even have that many tags!
model found here: http://sketchup.google.com/3dwarehouse/details?mid=de862f78d1412e5268d4f5a3519f61be
My second most "popular model" is a photo-textured version of someone else's posable version of someone else's colored version of someone else's extract of master chief from halo 3: with around 430 views and 250 downloads a week.
model found here: http://sketchup.google.com/3dwarehouse/details?mid=ec26ff8e5bcd25a25dfd2d7998768282
after those two models, the download rate plummets to 70, the 50, then 30, etc. I REALY don't get why certaion models are so popular