When I had an iPod touch, I found the internet totally pointless.  The only time I was able to use it was when I was around a computer, and any normal person would much rather cruise the web on a computer.  I never really played games and stuff, so a lot of apps were kind of pointless to me.  Most apps out now are far more functional on an iPhone, and some work for only the iPhone.  I found it quite an amusing tool for the first month, then really listened to music and watched movies in the car.  However, I now have an iPhone, and find myself using it WAY more and it is much useful.  I have internet WHEREVER I have service, which is a HUGE plus.  I have a camera, I can use ANY app in the app store, I have a microphone, the built in speaker is FAR better than an iPod touch, I can watch videos wherever I go.
If you really plan on playing games and being around wifi wherever you go, DEFINITELY get an iPod touch.  If you don't think you will use quite as much interactive stuff, go for the Zune.  It plays the songs the same, it plays the videos equally as clear.  If you really plan on being SUPER interactive and playing games, go for the iPod.