95% of the reason why I still play Fallout 3 is because it is a modder's haven (on the PC). And yes there are people who mod this game and use it for references more than they actually play. I play more than I mod but I am installing new mods all the silly goose time. It's like an endless supply of free candy!http://fallout3nexus.com
I've gotten every mod under the sun from that website for this game, including new missions, more weather, character skins, better AI programming, modernized weapons, realism mods, a vast array of clothes, hairstyles, eye colors...the list goes on and on.
I saw that people figured out ways to pose characters in whatever positions they wanted, so I think the game will be a valuable resource for references, definitely. I will be learning how to make the poses soon.
I've gotten some amazing screenshots from this game. So if you're interested, give it a shot and remember to checkout the Fallout 3 Nexus site for an absolutely amazing supply of resources to use.