I play in a rock band that derives a lot of influence from Led Zeppelin and Hendrix, and we're always discussing if guitar-driven rock music has the capacity to innovate and progress, or if it has to change, perhaps by engaging electronic timbres.

One example that it can still move forward is the post-rock stuff (I know only Godspeed You! Black Emperor). However, this introduces another question: Can we innovate AND retain some semblance of pop? Because Godspeed's degree of originality is inversely proportional to its poppyness.

One example that it must embrace foreign timbres is Radiohead's transition from OK Computer to Kid A; they felt that the generic rock sound had run its course, and so they started using synths, drum machines, etc.

What do you guys think?

I think that any type of music can evolve, but that classic rock sound is just that - a classic rock sound. You don't necessarily need synths to allow the sound to evolve, but there haven't been any new styles of playing that have really caught on.