Do new guitar based bands all sound too similar?  

This was being said way back in the sixties and seventies too, and when bands like Led Zeppelin and Pink Floyd were around. Each and every guitar sounds slightly different though, a Les Paul will have a different sound from a Fender. It is more the style in which the music is played.

Nah, they don't all sound the same. Anyone who thinks so isn't listening hard enough ;-)

I think similar sounding music has been around forever. I mean a lot of the hair metal bands I love sound reasonably similar which is probably why I like them all. I like the sound - the music, so similar is better to me. That being said, there are a lot of new bands I can't stand because I think they all sound the same. So for me it comes down to whether or not I like the sound being produced, not the bands themselves or what/how they play.

Some of my friends think this also. i agree with you though, there are many differences between the different bands