I notice on my iPod, the home button is more clicky, I guess. It makes a click sound once you push it. But the iPhone's home button seems more tightly useable, doesn't really make a clicking noise, and doesn't give too much feedback.
I noticed this too, but i think the iPhone is just bigger. I prefer the iPhone button.Well the iphone button is in fact bigger once you compared them but i like the iphone button more.
I don't know about the 2G touch, but the 1G touch home button is definitely a lot more "clicky" than the iPhone's. The iPhone button takes more effort to push down.