I really love the
allen-bradley photosensors from 2011 KOP. They come in super handy for indexing of game pieces, rpm measurement, elevator indexing (homing). The square body and threaded barrel make them easy to mount and they do a great job at rejecting IR light interference from the field lights.
We also had a good experience with the AMT10-V encoder this year. The CPR of the encoder can be adjusted via on-board dip switches and they can be mounted on shafts from 2-8 mm (1/4",3/16",1/8") making them exceptionally versatile. At $23 a piece we can keep lots spares around.