Cg trader seems to set the bar at under 50k polys to appropriately list it as a "low-poly" model. However, it depends on the scope of your work. Models meant for use on mobile platforms are relatively high poly at 50k. If your aim is to work on things which ought to appear in a PC or modern console game or some such, 50k is well within acceptable limits for something like a character or vehicle, but might be pushing it when it comes to something innocuous like a wall lamp for example. But as stated above, you can often replace complex geometry with things like bump, normal, light or other forms of mapping and coloring. But you want to avoid faking geometry on the albedo/diffuse textures because at the wrong angles it can look pretty bad. I hope it helps. Oh... i want to point out... I have a free model of a starship, it comes in two variants: one is about 60k polys and the other less than half that. The first has 2048 png textures and the second has them in 512. The first Roflstomps the second one in memory usage, but still gets downloaded more. I find it interesting because they look very similar.