Anyway, I'm thinking of doing a weapon restricted run in New Vegas where I can use only that weapon for all encounters. Does anybody have a recommendation for an interesting one?
That's a tough one. My favorite is the riot shotgun, but it won't show up at the Gun Runners until level 16, though some of the Omertas do carry them so if you max out Sneak and have a Stealth Boy, you might be able to pickpocket one.
That Gun is pretty powerful, especially with a crit build, but I feel it falls off after the midgame (I'm not big on crafting, so I've never taken Hand Loader and made some of the more outre varieties of ammo, which might keep it viable for longer, and people have taken down Lanius with a silenced .22 and a lot of ammo and patience so there's no way you couldn't do it with That Gun and standard ammo). As with most unique weapons, durability is awful, but if you work at leveling Repair up to 90, you can take the Jury Rigging perk at level 14 and then be able to repair it with any other handgun. If you get your Barter skill up to 50, you could also rush to the Strip, start the Talent Pool quest, give a job offer to the Lonesome Drifter, and convince him to give you the Mysterious Magnum in return.
If you prefer melee, you can always get Veronica, use her to get into the Brotherhood's bunker, and steal Paladin Hardin's super sledge off the shelf in his bedroom when he's not looking, since that's definitely an endgame weapon. You could also grab the shovel from Goodsprings Source, then use the parkour trick to get up to Chance's Grave without encountering any cazadores, and dig up Chance's Knife. (For that matter, you could go to Nipton, go up the faint trail to the Legion Safehouse, and follow the ridge to Wolfhorn Ranch to avoid the Viper ambush on the road below, then grab Chopper, though it's definitely not as good as Chance's Knife.)
Challenge runners have done some interesting single-weapon runs. Nerbit recently
did a run where he only used the Compliance Regulator, despite its low damage. Jabo did
a run where he had only 20 minutes to collect every non-quest item to be used and, on the basis of his Twitch chat's suggestions, used the MF Hyperbreeder Alpha, since ammo was going to be scarce and a recharger pistol is an obvious counter to that (melee weapons being out since healing items were also going to be scarce). Mitten Squad once used console commands to give himself
Miss Fortune's showgirl outfit and the Bad Luck Bringer, and completed the game using those as his only armor and weapon.
