[Blind-sysadmins] Wireless N card recommendation

Hello, I'm looking for recommendations for a new USB wireless card. It's got to be n compatible and can operate in both the 2.4 and 5 GHZ bands so it can connect to any network. Currently the two nano USB adapters have only 2.4 GHZ radios. Please let me know any recommendations and how you've found the cards you use and if you'd purchase them again? Thanks. Dave.