even though it would never happen as it would make to much sense, I would love Nintendo to purchase Sega/ip's, it would give them a more adult division of titles to win back people who perceive Nintendo as kiddy, they would gain genres that are severely lacking in-house with Nintendo , they would get good pedigree "Racing" , "Sports" series of ip's, a range of mascot games that suit younger crowds plus the legion of fans that grew up in the Sega Vs Nintendo era, a hell of a lot of mature and arcade titles that are lacking with Nintendo not to mention the back catalogue to compete better with xbla and psn.
With the range of ip's they wouldn't have to be so reliant on cranking out Mario and Zelda and eliminate black hole periods of no releases of new games to get people using their consoles daily and no longer just the "Party/Mario/Zelda" machine you dust off every few months.