I can't name all the artists that have influenced me so this page contains the ones I consider my MOST influential.
Jimi Hendrix: Guitar and musical pioneer! Been listening to Hendrix for a few years and now have a vast collection of his music. A big influence and his music inspired me to learn the guitar.
Muse: Modern rock gods! Classically influenced rock from a 3 piece. I've seen them live twice and their show is second to none! The first song of their's I heard was "New Born" and I've been a fan since.
The Red Hot Chili Peppers: Another big influence. Went to see them at Hyde Park in 2004 and just felt inspired.
Frederic Chopin: A true genius on the Piano. I have always liked his work, especially because he seemed to be doing something different to everyone else.
Blur: I was very much a Blur fan when I was younger and knew all their songs. They were much better than Oasis too!! Great song writing and again a good live act though unfortunately I've never seen them.
Duke Ellington: Another musical pioneer. The first time I really noticed his work was studying "Black and Tan" fantasy for A level and hearing those amazing tones, jazz with a classical influence.
Counting Crows: Great songs and a very versatile band. I suppose you might class them as middle of the road rock/pop with a strong country/folk influence. It don't matter, they are cool!
There are many more. I'm inspired by anything good that I hear. Whether it be a breath-taking live performance or just a good straight-forward song.