Is 4th generation ipod touch really worth it?

I've been meaning to get an itouch just to listen to music at work/school and for the apps. I have people who wants to sell me their itouches. I just don't know if I should spend a little bit more money for the $140 4th gen when I could get 2nd or 3rd gen itouches for about $50. I just really don't know if paying the extra is Really worth it. I mean, camera and microphone seems very handy at times when I'm out and about without my laptop, but then again its not a need since I have a perfectly working laptop and a Nikon d3100 I use to take pictures with. They offered me a VERY good price for a decent almost new itouches, but I can't seem to make up my mind…

You need much more than just music. For instance you are missing out on face time which i find to be so much fun. And the idea of taking pictures at will is fun too. You can't move around with the Nikon 3100 all the time.