Bethesda never reveals how many copies of each DLC are sold.

I want to make an inquiry of what DLCs that average mod users have purchased. Please participate in the poll above.

Im working on a new mod and I will decide if this mod uses DLC assets depending on the outcome of this poll.

I personally design all of my quest mods to use no DLC. That gurentee's that everyone can play it. I would only use DLC if it was a smaller project, and I could really do something awesome with the DLC content. So far for my two New Vegas mods, the DLC could only add a few minor things that aren't worth limiting who can play it. Only use DLC if you are doing something huge with it.

I design mods for myself, if I want to use some assets from a DLC that I have, even if its relatively minor, so be it. I'm not going to let other people influence what I want to do with my mod (within reason)

DLC: Sure why not if it's necessary.
Pre-order Packs: There are barely any new assets for a new mod anyway. I don't see this happening unless that mod edits the packs.

I preordered the game and own all current DLC. Although I bought all the DLC on sale (thank you, 75% off Steam sale), I'll have to buy Lonesome Road immediately because I'll need to make a pack to add energy shields to it for my new mod.

I think it's fine to use DLC assets in your mods as long as it improves them. It might be silly if you just stuck a wall from Dead Money in something, but if you're really benefiting, then use whatever you can.

Haven't made a single mod for NV, but all my Fallout 3 mods are intended to use only vanilla resources. However, two of my mods use Broken Steel as the story wouldn't make sense without it.

From my perspective as a player, I prefer it if mods don't require DLC (unless explicitly made for a DLC, of course).
Although I so far own all NV DLCs, I guess not all do and not being able to use a cool mod because you don't have all the DLCs can be a bit frustrating.

That said, I do appreciate if modders incorporate features from DLC and offer compatibility packs and/or expansions to their mods.