I use WinAMP to create my playlists, for SAM, but have never used it to DJ with. MIXX is a bit complicated if you are just starting out. SAM is very easy to use and set up, especially if you are a beginner like I was. I have some DJs, at my station, that love VirtualDJ. VirtualDJ does cost money, though. I have used various versions of SAM for the past 4 years now. I was able to get the full package at half price, during the holidays.
I noticed that SAM now has a DJ package just for Second Life. It's $15 a month, for personal use. You might want to try it out for a month and see if you like it or not. Here's the link . Hope this helps.