Best Guitar Hero.

Which one is the best in terms of songs and which is one is hardest? In your opinion..

Also, does the wireless Kramer guitar work with the older games?

I think Guitar Hero 1 is the best overall, in that its songs are the most fun to play, but that's very much a matter of personal taste.

As for the hardest one, I think most people would agree that Guitar Hero III takes the cake.