It depends greatly on what the models are doing and how many others are in the scene.
The maximum poly count is more important.
That is going to vary greatly depending on the end user's processor and gfx card.
My base for any program is 300 MHz and 8 Mb VRAM.
I have a really crappy SiS on an old Celeron machine, and it serves the purpose of define the lowest possible machine.
You don't get a lot of polys with THAT!
Also, it depends on how tight the code is.
There are a few major algorithms that need a couple for-next loops to run, and if you run them on DBC, you're dead at just a couple hundred polys.
Try writing a 3-D math prog with DB some time.
Once you get up to do a 3-D model of an y=x^4 + x^3 . . . you will have a brain aneurysm at how slow it all runs. And none of this has anything to do with 3-d, since you don't want to sync any of that to screen until the end.
God forbid you need something that moves models and runs that type of math at the same time!
We can't stop here! This is bat country!