Yay, level 50.
Where do I get the best loot?
Edit: I'm a gunzerker, by the way.
From the gearbox forums
Assault Rifles
Seraphim[DLC1] - Seraph Vendor
Madhouse - Mad Dog*, Lynchwood
Veruc - Mobley, The Dust
Hammer Buster - McNally, The Dust
KerBlaster - Midge-mong, Southern Shelf
Shredifier - Unknown
Scorpio - Quest reward from "Bearer of Bad News" (Unique)
Evil Smasher - Quest reward from "The Chosen One" (Unique)
Hail - Quest reward from "Bandit Slaughter: Round 5" (Unique)
Stomper - Quest reward from "Hungery Like the Skag" (Unique)
Stinkpot[DLC1] - No Beard(Does not Respawn), Oasis
Captain Blade's Rapier[DLC1]- Quest Reward from "Message in a Bottle (Hayter's Folley)"
Boom Puppy[DLC2] - Quest reward from "Walking the Dog"
Angry Kitten[DLC2] - Quest reward from "Everybody Wants to be Wanted"
Pistols
Devastator[DLC1] - Seraph Vendor
Gub - Laney, The Fridge
Hornet - Knuckledragger, Southern Shelf
Maggie - Mick Zafod, The Dust (Side with Hodunks)
Thunderball Fists - Captain Flynt, Southern Shelf
Gunerang - Rakk Man, The Fridge
Unkempt Harold - Savage Lee*, Three Horns
Infinity - Doc Mercy, Three Horns Valley
Logan's Gun - Wilhelm, End of the Line
Dahlminator - Quest reward from "The Lost Treasure" (Unique)
Teapot - Quest reward from Tiny Tina "You are cordially invited"(unique)
Judge - Assassin Oney, Southpaw Steam and Power(Unique)
Rubi - Quest reward from Moxxi "Rakkaholic Anonymous" (Unique)
Fibber - Quest reward from "A Real Boy" (Unique)
Veritas - Quest reward from "Clan Wars: Wakey Wakey" (Unique)
Flint's Tinderbox - Captain Flint, Southern Shelf (Unique)
Gwen's Head - Found in a box near the Buzzard camp in The Dust (Unique)
Lady Fist - Quest reward from Una Mailbox in "Uncle Teddy" (Unique)
Law - Sheriff, Lynchwood (Unique)
Greed[DLC1] - Spoiler: Captain Scarlet during "Treaures of the Sands"
Little Evie[DLC1] - Magnys Lighthouse Kill Mr. Bubbles without hurting Lil' Sis. Speak with Lil' Sis afterwards to recieve Little Evie
Pocket Rocket[DLC2] - Purchase from Torgue Vending Machines
Rocket Launcher
ERROR MESSAGE ERROR MESSAGE[DLC1] - NPC Weapon used by Master Gee.
Ahab[DLC1] -Master Gee, Hayter's Folley / Seraph Vendor
Badaboom - King Mong, Eridian Blight
Pyrophobia - Incinerator Clayton, Frostburn Canyon
Bunny - Chubby enemies
Nukem - Black Queen, The Dust
Mongol - Dukino's Mom, Lynchwood
Norfleet - Vermivouris / Hyperius, Washburne Factory
Roaster - Quest reward from "Note to Self-Person" (Unique)
Creamer - Quest reward from "Creature Slaughter: Round 5" (Unique)
The Hive - Saturn, Arid Nexus Badlands (Unique)
12 Pounder[DLC1] - The Big Sleep, Hayter's Folley
Shotguns
Retcher[DLC1] - Seraph Vendor
Conference Call - The Warrior
Striker - Old Slappy, The Highlands
Deliverance - Tumba, Wildlife Preserve
Flakker - The Warrior
Sledge's Shotgun - Smash Head, The Fridge
Slow Hand[DLC2] - Badassaurus Rex/Piston, The Arena
Thre Dog - Assassin Rouf, Southpaw Steam and Power (Unique)
Triquetra - Quest reward from "Clan Wars: End of the Rainbow" (Unique)
Moxxi's Heartbreaker - Quest reward for siding with Moxxi in "Safe and Sound" (Unique)
Shotgun 1340 - Quest reward from Marcus during "Out of Body Experience (Unique)
Blockhead - Badass Creepers, Caustic Caverns (Unique)
Octo - Quest reward from "Slap Happy" (Unique)
Roksalt - Quest reward from "Splinter Group" (Unique)
Landscaper - Quest reward from "Family Fued: Dueling Banjos and Fiddles" (Unique)
Tidal Wave - Quest reward from Hyperion Mailbox in "Uncle Teddy" (Unique)
Teeth of Terramorphous - Terramorphous
Jolley Roger[DLC1] - Quest Reward from "Just Desserts for Desert Deserters"
Captain Blade's Orphan Maker[DLC1] - Quest Reward from "Message in a Bottle(Oasis)"
Sniper
Patriot[DLC1] - Seraph Vendor
Pitchfork - Terramorphous
Invader - Saturn, Arid Nexus Badlands
Skullmasher - Son of Mothrakk, Wildlife Preserve
Volcanoe - The Warrior
Longbow - Badass Creeper, Caustic Cavern
White Death/Lyuuda - Gettle, The Dust
Buffalo - Quest reward from "Demon Hunter" (Unique)
Fremington's Edge - Assassin Reeth, Southpaw Steam and Power (Unique)
Trespasser - Quest reward from "Animal Rights" (Unique)
Sloth - Quest reward from Mordecai in "Rakkoholics Anonymous" (Unique)
Morning Star - Quest reward from "Hyperion Contract #873" (Unique)
Chère-amie - Quest reward from "Hyperion Slaughter: Round 5" (Unique)
Pimpernel[DLC1] - Quest Reward from "Don't copy that floppy"
Cobra[DLC2] - Has a low chance of dropping off "Burners" in the Campaign of Carnage DLC. Confirmed here
SMG
Actualizer[DLC1] - Seraph Vendor
Tattler[DLC1] - Seraph Vendor
Slagga - Hodunk, The Dust
Emperor - The Assassins, Southpaw Steam & Power
Bitch - BNK3R
Hellfire - Scorch, Fropstburn Canyon / The Warrior
Baby Maker - Madame Von Bartlesby, Tundra Express / Mad Dog, Lynchwood
Miss Moxxi's Bad Touch - Reward from tipping Moxxi(Unique)
Miss Moxxi's Good Touch - Reward from tipping Moxxi, no set amount, can be got constantly (Unique)
Bone Shredder - Bonehead 2.0, Arid Nexus Badlands(Unique)
Bane - Quest reward from "The Bane" (Unique)
Lascaux - Found in a pond in the caves of Frostburn Cavern, respawns (Unique)
Chulainn - Quest reward from "Clan Wars" (Unique)
Commerce - Assassin Wot, Southpaw Steam and Power (Unique)
Sand Hawk[DLC1] - Quest Reward [from "Whoops"
Shields
Evolution[DLC1] - Seraph Vendor
Big Boom Blaster[DLC2] _ Torgue Seraph Vendor
Sponge[DLC2] - Torgue Seraph Vendor
Pun-chee[DLC2] - Torgue Seraph Vendor
Hoplite[DLC2] - Torgue Seraph Vendor
The Transformer - Pimon, Wildlife Preserve
Whiskey Tango Foxtrot - Chubby Enemies
The Sham - BNk3R
The Bee - Hunter Hellquist, Arid Nexus Boneyard
Fabled Tortoise - Blue, Caustic Caverns
Black Hole - Foreman, Opportunity
Impaler - The Warrior
Neogenator - Spycho, Frostburn Canyon
Hide of Terramorphous - Terramorphous
The Cradle - Henry, The Highlands
Flame of the Firehawk - Quest reward from Lilith's Cult Mission (Unique)
Deadly Bloom - Quest reward from "Helping Out Overlook" (Unique)
Order - Quest reward from "BFFs" (Unique)
Love Thumper - Quest reward from "Best Mother's Day Ever" (Unique)
Aequitas - Quest reward from "Clan Wars: Wakey Wakey" (Unique)
1340 Shield - Quest reward from Dr. Zed in "Out of Body Experience" (Unique)
Pot o' Gold - Drop from Bagman(Doesn't Respawn) during the Quest "Clan Wars: End of the Rainbow" (Unique)
Captain Blade's Manly Man Shield[DLC1] - Quest Reward from "Message in a bottle(Wurmwater)"
Grenades
O-Negative[DLC2] - Toruge Seraph Vendor
Meteor Shower[DLC2] - Torgue Seraph Vendor
Crossfire[DLC2] - Torgue Seraph Vendor
Bonus Package - Boom Bewm, Southern Shelf
Bouncing Bonnie - Loot Midgets*
Fastball - Boll*, Three Horns
Fire Bee - Unknown
Leech - The Warrior
Quasar - Ultimate Badass Varkid
Rolling Thunder - Wilhelm, End of the Line
Storm Front - Rat Brothers, Bloodshot Stronghold
Pandemic - Mortar, Sawtooth Cauldron
Nasty Surprise - Vermivouris
Breath of Terramorphous - Terramorphous
Kiss of Death - Quest reward from "Hell Hath No Fury" (Unique)
Fuster Cluck - Quest reward from "The Pretty Good Train Robbery" (Unique)
Sky Rocket - Unlocked with Special Editions of BL2
Captain Blade's Midnight Star[DLC1] - Quest Reward from "Message in a bottle(Lighthouse)"
Class Mods:
Slayer of Terramorphous Siren - Terramorphous
Legendary Siren - Vermivorous*
Legendary Soldier - Vermivorous*
Legendary Berserker - Vermivorous*
Legendary Hunter - Vermivorous*
Legendary Mechromancer - Vermivorous*
Relic:
Blood of the Seraphs[DLC1] - Seraph Vendor
Might of the Seraphs[DLC2]- Torgue Seraph Vendor
Blood of Terramorphous - Terramorphous
Sheriff's Badge - Drops from Sheriff of Lynchwood (Unique)
Deputy's Badge - Quest reward from "Showdown" (Unique)
Moxxi's Endowment - Quest Reward from the "The Good, The Bad and the Mordecai"
Lucrative Opportunity Quest Reward for siding with Marcus in "Safe and Sound"
Vault Hunter - Unlocked with Premiere Club
The Afterburner - Quest Reward from "Positive Self-Image"
Captain Blade's Otto Idol[DLC1] - Quest Reward from "Message in a bottle(Rustyard)"