I need to know so I can develop my own game... Or at least that is my intention....

XSI or Maya or 3DS Max.

They use Maya, but it doesn't matter. You need to set the output of the model to a custom one that Valve made, so If you want to make models to the game, download the output and pick a software.

I reccomend XSI.
1) Valve used it in P2
2) It's free if you use the mod tool.
3) Imports/Exports .SMD, .VMF, .DMX

They use Maya but it's shareware. There are a couple of free programs you can use to make models like kHED, MilkShake 3D or Softimage XSI.

https://developer.valvesoftware.com/wik ... y:Modeling

You can use 3DS Max with student license, its for 3 years.

So once I get the models done, what program could I use to develop my own FPS, list anything besides Blender.....

You want to create a First Person Shooter or Frames Per Second? The first makes more sense than the second.

I would first try 'modding' for Half-Life: 2 (as the source code is released) first. Creating a game from scratch is a very long and difficult process, usually done by a highly motivated, skilled and organised team.

I use softimage (free version) if I want to do anything with models. Animating is done differently depending on which program you use, if you are using Softimage, look up animation tutorials on the Maya tutorial website.

I use student version 3ds Max... it's the best.