How to duplicate multiple times along x-axis with set distant apart?

Is there someway to do muliple duplications along a particular axis with a set offset. I know of the dupliframes and using a bezier curve path. but is there another way??

That is exactly what an Array modifier will do for you. Check it out in the Wiki:

sorry i didnt specify, but i;m not duplicating objects but faces in edit mode. I want something like 10 circles in a row at a set distant apart. Or another random polygon. So how would i go about doing this without manually doing each individual one

Extrude Dup in Mesh Tools panel is a good starting point.
It extrudes selection away from the view at given offset. It works like multiple extrude so the borders are connected.
You have to find a way to delete the conecting edges and to fill the holes if needed and this is not that hard to solve.
If you give more defined example of what you want to achieve there might be other solutions.

I’d of thought the array modifier that DichotomyMatt said would of done this best. Just apply the modifier when your done to create the mesh. If you want it to follow a set path you could also tell the array to follow a curve before applying it.