For interfacing those rotary encoders, you'll probably want to use my Encoder library....
http://www.pjrc.com/teensy/td_libs_Encoder.html
It provides "4X" counting, so a commonly available 24 pulse/rev encoder will give you 96 steps per revolution. Of course, there are much higher precision encoders available, but they tend to be expensive. Maybe for your application they're worth the cost?
The library works best if every encoder uses at least 1 interrupt pin. Arduino Uno only has 2 such pins, so if you plan to connect more than 2 encoders, you might want to consider using a board with more interrupts available.