Lincoln's Repeater is my headshot gun of choice...I like it even more than the Reservist's Rifle (named sniper rifle) because it carries more ammo at a time, and does more damage.
Plus, sniper rifles and .308 ammo is fairly uncommon, so it's tough to keep them maintained and with adequate shots.
[Sblock=More uniques
![Devious :] :]](http://www.enworld.org/forum/images/smilies/devious.png)
Smuggler's End - Laser Pistol that does 19 damage fully repaired. Elder Lyons' wall safe (which is NOT stealing for some reason) in the Citadel.
Reservist's Rifle - Sniper Rifle that does much better damage, but only carries 3 rounds per clip. A crazy Oasis guy has it in a Chapel not far from the satellite towers in the northwestern area of the map.
Sydney's Ultra 10mm SMG - The relic hunter you can team up with in the National Archive has a SWEET customized SMG. To get it, you must either let her die, kill her, or encounter the corpse of her father in the Reilly's Ranger quest. Explore the hotel thoroughly and you'll see a skeleton on a bed with an audio log beside it. That's her dad. After you finish the National Archive, Sydney will trust you enough to open up and tell you about her father abandoning her. Give her the log. She'll be grateful, and decide to leave the merc biz behind, and give you her gun plus some ammo for it. This gets you good karma. If you don't find her dad before finishing the National Archive, it's okay. She goes to the Underworld to hang out. You can bring the audio log to her there for the same result.[/sblock]
There are a LOT of really cool little side stories and non-quest goodies. Here's a few:
[sblock=Fun Side Things]Southwest corner, not far from Girdershade, look for the Dunwich building. Check it out, and be sure to explore all of it. Creepy and fun!
Also in the southwest, though not as far west, is Andale. This place was just awesome, mainly because it's so low key. Once you figure out what's going on there though, you'll get the screaming meemies! Gloriously dark.
Hubris Comics, in the south side of the DC Ruins. A weird detour, but has good loot, a weirdly entertaining text adventure minigame, and a crazy dude with a minigun.
There's an old Armory in the northeast that's -heavily- guarded by raiders, but is swimming in good loot if you can get past them. Be good at hacking and/or lockpicking, as the main armory room is still sealed. Be warned the raiders are well armed, including one with a missile launcher.
There's a ruined car factory north of the DC ruins that is infested with giant ants. There's a queen in the assembly line area...a tough fight, but great exp. You get ant pheremones from her, which can be useful in a side plot in Rivet City.
...I could go on like this forever. There's an -astonishing- amount of content in this game![/sblock]