I would consider the Milkshape 3D format, MS3D, it's binary and fast to load and much easier then 3DS.

I have written my own format for Phoenix through, but that's just how i roll.

And for polygon count, in recent game the trend is to use fewer polygons then a few years ago and using normal mapping and other effects to raise the quality. I would say that 10-20k polygons per model is nothing impossible.

There's a nice list of vertex count here

http://forum.beyond3d.com/showthread.php?t=43975

And you can check the code for my MS3D loader here: http://andreaznas.dyndns.org/phxModels.7z