I decided to buy all the autodoc implants, medicine stick, the bozar, and all the ammo at the great khan armory. then used the jackpot from the Sierra Madre Casino to acquire all the mods for the DLC weapons

I put them on display in my Underwater House.

Nothing. By the time I actually comepleted Dead Money I had so much stuff I couldn't find anything I wanted/needed. I was just going to sell them but none of the vendors in the game had enough caps. However, since I am now playing a modded playthrough I hope to use them this time.