I see lots of people are voting for Capcom. To be honest, I don't think it would be an effective acquisition.
Capcom atm is crap and probably needs an internal reorganization, Nintendo doesn't have the resources and the install base to even properly support its own IPs (F-zero, metroid, Starfox, etc.), let alone Capcom IPs.
Imo what would make more sense form the options suggested, would be a spinoff of the Xbox division to merge with Nintendo. They would complete each other, MS has excellent 3rd party support but they don't have enough 1st party studios to compete with Sony, on the other hand Nintendo has stellar 1st party games and abysmal 3rd party support. MS is strong in west, while Nintendo is strong in japan. A MS-Nintendo console would have the strongest selection of multipalyer IPs (local and online - 1st party and 3rd party) COD, Halo, Gears, Kart, Smash Bros, Killer Instinct. It would have both M rated games and family games.
On the other hand a merge with Sony would be more problematic imo. First, while MS and Nintendo have the multiplayer value in common, Sony 1st party IPs are more about cinematic experiences, quite the opposite of what Nintendo is offering. More importanly, Sony and Nintendo on the same boat would have just too many 1st party studios and IPs, this would just create the same situation of WiiU where palyer would only buy high-quality 1st party games while overlooking 3rd party games. In the end, Sony or Nintendo (or both) would have to cut their own content and 1st party studios in order to leave more opportunities to 3rd party companies.
