XT 3X10 speed, they aren't the top components in the world, but you can put some miles on them before they will need to be switched. Get the long cage rear so you always have the option to go for a bigger bailout. Also you my end up needing to get the mount for the bottom bracket refaced with the newer outboard bearing bottom brackets, I don't know a lot about that frame.
Shimano XT 10sp Drivetrain Groupset Builder | Chain Reaction Cycles

after that it's just your favorite bar, some brakes and brake levers and cables.
I don't know anything about 26" rims so someone else will have to jump in here.