I'm thinking about that. I have both genders of Nidoran in Soul Silver as I type, both sitting at Lv.12. I can't import then yet, and have been hedging on developing them because females apparently lose their ovulational abilities once they fully evolve (whereas Nidoking can breed). Someday I will have to evolve them in there, however.
I guess importing Nidoran into Black would allow me to freely develop either or both of them if I so want to in Soul Silver, or later in D/P/P once I have the National Dex. So I ask this: is yours a Nidoran♂ or Nidoran♀? I prefer the female (♀) as apparently there is some chance of breeding it to get a male, whereas the male cannot breed a female at all. Further, the Nidoking and Nidorino can still breed, whereas the Nidoqueen and Nidorina cannot; after I breed a few Eggs, if I still don't have a male, I can always breed for one. Even so, they are separate Pokédex entries, and I do need both eventually. At worst, I can always import to White 2 someday if needed from Gen. IV.
So female first, but if there's any chance at both, what would you like for the second?
I have about five or six Moon Stones in my inventory. I can evolve those ones myself, unlike the others. Getting anything at the lowest point in the evolutionary line would assist in clearing all Pokédex entries for that line. Ones for other stones I will have to breed unless people can trade stones (no doubt they intended us to trade our primary stones).
I didn't have much in mind; however, what would interest me is something I don't have yet. To put that simply, with exception to Pichu/Pikachu/Raichu (got Raichu on Friday), if it's not available in Black or White at all, I am likely interested in it. If it requires a stone to evolve, I am DEFINITELY interested in it since I don't have easy access to stones in Black or White (relying on the PokéAthlon and my eventual catching skills in all Gen. IV games to complete that collection). I do still need some White Forest exclusive Pokémon however.
I see Adrian's already offered. I was just coming to offer a Rufflet too, but it seems he'll get it there first. That's fine, but if you're interested, I'm offering SuperZoruas™ and Pichus (the former knowing Volt Tackle) if you need either of those; note that Pichu/Pikachu/Raichu are not found in Black OR White anywhere.