You will need only X10 for the basic stuff. If your looking to make terrain and stuff like that then you can use custom media from other users or make it yourself using modling software :
Fragmotion
Milkshape
Wings 3D
XSI Tools
3DS Max
Blender
You can download custom content from the sites below. Model packs can be bought which are made by users of the fpsc community. I reccomend since your making a combat game , you try model pack 9 and 10.
Here is the sites you may want to visit :
Fps-Files
fps-free
X9 site (Model packs to the left of the screen)
I wish you the best of luck with x10.
Just a little heads - Use tab to open the ingame menu for effects if you didnt already know. You can also use scripts to change the effects using a trigger zone
