It will normally be printed on the bulbs socket, and on the package. 6500k is the ones that will give a pure strong "white" light, and the 2700k will give a warm soft light.
Is the reason for not using MH or HPS initial or running cost? If it is the initial cost you should be aware that you will sooner or later need stronger lights, 105-200w CFL, they are not cheap, and a 200w HPS/MH with ballast will cost more or less the same at the end. Also remember that you will probably also need reflector, and that high wattage CFL use E-40 socket and not the usual E-27. Difference in price will vary, but you will find a complete HPS/MH system for 90-110euro, a 105-200W CFL system will cost you 10-20euro less.
If it is running cost you should check out LED grow lights....., also fluorescent tubes, but that might be expensive.
For more info on lights you could check out the following link:
http://www.4hydroponics.com/lighting/lightingBulbs.asp
Hope this made some sence, if not I´m sry! Best of luck....