I upgraded from using CD's to laptop a few years ago, I use PCDJ FX. I have to say it has been fantastic to use and makes life so much easier (especially searching for a request). On the other hand you feel almost fraud it is that easy, plus unless you get a very high quality laptop or an expensive soundcard the quality will never be as good as it is from a cd. For this reason I have recently changed to A twin media player called DJ tech U2, it has a usb port for plugging in your pendrive. The quality is brilliant. I bought it from Ebay imported from USA. It cost roughly with postage £250.00.
