>>71756389Get Fallout 3 AND Fallout NV, then install Tale of Two Wastelands (adds the entirety of Fallout 3 to Fallout NV). It's WAY more stable than just playing Fallout 3 by itself, and you get the opportunity to carry your character to New Vegas as-is.
If you're going to focus heavily on mods though, go with Fallout 4. It has mods fixing everything wrong with the base game.
Both TTW and Fallout 4 have ATF mods.