The U/B Faeries deck in Standard has been a tournament staple since the release of the Lorwyn/Morningtide block. Of all the tribal themes to emerge from that block, Faeries has been far and away the most popular, and is a consistent Top 8 deck in major tournaments. It wins via an Aggro-control strategy, playing efficient creatures which also act as counterspells and board manipulation, coupled with the formats best spells like Cryptic Command and Thoughtseize.
Here is a sample decklist which was piloted by Antti Malin to 1st place at the 2008 World Championships.