Diff between 3G and 4G 20gb ipods?

What are the differences between a 3G ipod and a 4G ipod?

Anywhere i can find a comparison between the two? Or would someone be kind enough to provide a comparison in functions? Let's compare both the 20gb models..

Well, I have a 4g 20gb, from what I saw on other peoples ipods the 3g had buttons on the top of the ipod below the screen, the 4g, the buttons are incorporated into the touch wheel. Also the 4g is a little slimmer, I only know that because I am using a 3g case for my 4g. 4g cases are hard to find. The click wheel on the 4g is gray as well, not white like the 3g. Also the 4g has mechanical buttons, not touch buttons like the 3g, personally I prefer the 4 over the 3, but I have heard different opinions.

3rd Generation
bout 8 hours battery life

4th Generation
Newer firmware (allows for multiple on the go playlists)
12 hour battery life
Click wheel instead of the touch sensative buttons

trpnmonkey41 said:

3rd Generation
bout 8 hours battery life

4th Generation
Newer firmware (allows for multiple on the go playlists)
12 hour battery life
Click wheel instead of the touch sensative buttons

Click to expand...

...and the 4th gen is a little bit thinner than the 3rd gen.

The 4th gen also lakes all of the equipment the 3rd gen had, you have to buy it seperately (dock, cable remote, beltclip holster, all together worth about 120,- euro)