ShowMan

hey there- I'm extremely new to anything "home theater" related so bear with me here:

I finally got a 5.1 Pioneer receiver and I want to set up some surround sound speakers.

HOWEVER I've got a pair of Definitive Audio tower speakers (just a 6" sub looking speaker and a small tweeter) that I don't really want to get rid of because they sound really good.

can I intergrate these tower speakers into my surround sound set up by using them as the "front" speakers than buying a pair of seperate "surround" speakers for the back, a seperate "center" speaker than maybe a subwoofer? (the Definitives already put out very nice bass for my apartment so maybe not necessary)

will these larger seperate tower speakers not be as ideal as just using a set of little surround sound speakers that they sell with the surround sound kits?
should I just throw the Definitives out because the days of stereo are over? I really like my tower speakers but I don't know if they'll work in a surround sound set up. thanks