Fallout: New Vegas

For 3440x1440:
In the options panel in the New Vegas launcher
Select 16:9 aspect ratio
Set the resolution to 2560x1440

Edit Fallout_default.ini in game directory, Fallout.ini and FalloutPrefs.ini in Documents\My games\FalloutNV:
(FalloutPrefs.ini directly affects the game so you only have to edit this one)

[Display]
Modify iSize w from iSize W=2560, to iSize W=3440
Change fDefaultFOV from fDefaultFOV=75, to fDefaultFOV=95

[RenderedTerminal]
Change fRenderedTerminalZoom=33 to fRenderedTerminalZoom=75

HUD issues with bezel compensation.

Fixing the UI is the same as Fallout3:

edit the three .ini-files (Fallout_default.ini in game directory, and Fallout.ini/FalloutPrefs.ini in documents/games/FalloutNV):

[Display]
fDefaultFOV=120.0000
bEnableEyefinity=0
iSize W=6048
iSize H=1080

[Interface]
iSafeZoneXWide=925
iSafeZoneYWide=15
iSafeZoneX=925
iSafeZoneY=15

To make the pipboy/terminals more usable:

[Fonts]
sFontFile_1=Textures\Fonts\Glow_Monofonto_Large.fnt
sFontFile_2=Textures\Fonts\Glow_Monofonto_VL_dialogs.fnt
sFontFile_3=Textures\Fonts\Glow_Monofonto_Medium.fnt
sFontFile_4=Textures\Fonts\Monofonto_VeryLarge02_Dialogs2.fnt
sFontFile_5=Textures\Fonts\Glow_Monofonto_VL_dialogs.fnt
sFontFile_6=Textures\Fonts\Glow_Monofonto_VL_dialogs.fnt
sFontFile_7=Textures\Fonts\Baked-in_Monofonto_Large.fnt
sFontFile_8=Textures\Fonts\Glow_Futura_Caps_Large.fnt
sFontFile_9=Textures\Fonts\NVFont_Test.fnt

[RenderedTerminal]
fRenderedTerminalZoom=88