Usually a main player character can be around 10K polys (or up to around 25K or more if you need detailed cutscenes) and objects can be around 1K polys or less.
However, poly count is not that important on desktop. For mobile and web you still have to watch out. But on a high end desktop machine, even several million polys for a whole scene is acceptable.
I think if you use LOD and other culling techniques, and keep the entire visible scene to around 1 million polys, you should be fine.
That said, the shader complexity is usually the bottleneck first, especially if you use things like parallax mapping or fullscreen effects like SSAO. So I wouldn't worry too much.