Cat5e unless you can get cat6 cheaper. Both will let you run at 1g to 100 meters. You could put in cat6a if you were thinking about 10g but it is likely many years off.
In any case make sure you get solid copper wire do not buy CCA cable even though it is cheaper. CCA cable does not meet the certifications and it tends to have strange issues with some of the wall plate connectors commonly used.