Models: how big and how many?

I'm doing a bit of modelling for a project I'm planning to build in the monkey engine and I wanted to see how big/detailed I should make my models because it's not an area I know a lot about and blender wants me to be using 10000000000 polygons. More or less.

What I need to know is how many polygons I should be putting into my models if I want things to run reasonably smoothly. Given that I'm not entirely sure how I'm going to do things (and that it will partly depend on the responses to this) I guess it's most sensible to ask how you guys are doing things…

What kind of polycounts are your "character" models? How many do you expect to have on screen at any given time?

What about other background models- are you running a detailed background or something very simple?

Do you feel like you're pushing your system with that or does it run very happily?

What kind of systems do you intend to run your application on? The upcoming batch of "next-gen" (a term i generally dislike) games seem to target ~5000 triangles for an average normal-mapped character model. The most advanced models can have double that amount. If you want your game to run on older hardware you probably need to be a lot more conservativethan that with your polycount though.

Basically, my modelling isn't going to be good enough to justify a really high polycount so I might as well target lower spec systems, I reckon. I'm thinking probably current to previous generation graphics. If it runs reasonably well on my machine ( amd 3000+, 128mb GeForce video card) I figure by the time I'm done writing the code that will be a pretty low spec anyways…