For 2 plants, i'd go for either 1x 250w or 2x 125w. For Vegging use a 6500K bulb (blue light / daylight) on 18hrs, then switch to a 2500k bulb for flowering (yellow/orange light) for 12/12.
Personally, i veg with CFL, then switch to HPS for flowering. A 250w hps is far superior to 250w CFL...