If you really want VERY high light plants then yes get 260 watts. If not I think 2 x 65 for a total of 130 would be plenty. That will give you close to 3 wpg (actual volume of water) of power compact light! I would say even with that you will probably want to add CO2.
I think only VERY high light plants won't be able to grow with that light. If it was me I would spend the extra money saved from not buying 2 additional bulbs and buy something else useful, pressurized co2 maybe?