Nitecore started off their really popular SmartPD series with the D10 and EX10. They had pistons to control the light instead of regular switches and infinite brightness. Next up were the SP versions, which got rid of the infinite brightness, but added strobe and SOS. The newest versions, the D11 and EX11, combine the best features of both, giving you access to both infinite brightness and the flashing modes.
The lights have some slightly redesigned bodies, but they are still nice and compact and have the same grippy feel with knurling covering most of the body. If you have never seen the SmartPD lights, then they are something worth checking out. They have a piston going the length of the body that contacts the head when pressed, giving you reliable operation and a cool feel that is very different from a traditional switch.