If you can afford it...replace the rotors as well. BUT...if its a "NEED TO DO IT ASAP" job. Just go the pads.
My personal experience -
I found my new set up very nice - EBC Greenstuff pads are nice. Although some have raised their concerns about the dust that it does leave on your wheels. I havent experienced this as yet.
If its all your brakes that need replacing and your wanting to go the race/street type brakes (Slotted/drilled) - my advice is to stick with solid rear rotors and maybe a better rear pad. As for the front - personal choice - but i have found that with the current EBC Turbo Groove rotors and G/Stuff pads work VERY well together.
I bought all my stuff from Autospeed - and then got them fitted from the brake place down the road. All up cost me around 1k for all supplied and fitted - (Holden was going to charge me just for the standard rear pads supplied & fitted - $250!!)