Fallout: New Vegas Add-ons

Caravan Pack
The Caravan Pack is a Fallout: New Vegas add-on that gives the player access to of extra items at the start of the game. It was announced as a pre-order bonus exclusive to Steam, Wal-Mart, Mighty Ape, and Play.com. It includes lightweight leather armor, the sturdy caravan shotgun, 4 repair kits, and a pair of binoculars.

Classic Pack
The Classic Pack is a Fallout: New Vegas add-on that gives the player access to extra items at the start of the game. It was announced as a pre-order bonus exclusive to the GameStop, GAME and EB Games chains of stores. It includes an armored Vault 13 suit, a weathered 10mm pistol, a Vault 13 canteen, and 5 stimpaks.

Mercenary Pack
The Mercenary Pack is a Fallout: New Vegas add-on that gives the player access to extra items at the start of the game. It was announced as a pre-order bonus exclusive to the Best Buy and JB-Hi Fi (Australia) chains of stores. It includes lightweight metal armor, a mercenary's grenade rifle, 3 super stimpaks, and 3 doctor's bags.

Tribal Pack
The Tribal Pack is a Fallout: New Vegas add-on that gives the player access to extra items at the start of the game. It was announced as a pre-order bonus exclusive to Amazon.com and direct2drive.com. It includes tribal raiding armor, a broad machete, 5 bleak venom doses, and 10 throwing spears.

DLC
Bethesda has confirmed that there will be post-release DLC for Fallout: New Vegas coming out 22 December 2010, called Dead Money. It will be exclusive to Xbox Live. In Bethesda's press release about the add-on, it is said "More details about plans for additional content will be released in the coming weeks.". On November 17, Major Nelson tweeted the name, date and cost for the DLC.

You can read the official Bethesda press release here, and the Tweet here.