Well, 1200 is relative to how many units you plan to have running around at the same. If you're playing a FPS tank game like Tread Marks, that perfectly OK. Now, if you were trying to do a Command & Conquer tank rush, 1200 might be insanely high.
From Nick and Andy's comments, I gather that 1200 is for up close models with a dynamic LOD routine taking it down from there. That sounds very workable for battlefield game that is somewhere in between an FPS and an RTS.
My next project is going to be a turn based tactical combat game, I have the luxury of using as many polygons as I need. But, I still have to be realistic with my polygon budget. I'll probably use an aggressive fog of war model to cut down on the workload.
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TAZ