I have to agree with futurolvidado and Moodiesfan41: If we are talking mellotron and prog/pop music, to leave out the Moodies is like discussing the history of manned flight and leaving out the Wright brothers. Many of the keyboardists of the groups mentioned below directly or indirectly credit Mike Pinder and the Moodies with turning them on to the Tron. Yeah, some may credit the Beatles (Strawberry Fields Forever) or the Stones (2000 Light Years From Home) but who turned THEM on to the Tron? Yup, Mike Pinder. Not to mention the sheer lushness (for which they were often criticized) of much of their earlier music, all due to the Mellotron. Is there a better Tron album overall than To Our Children's Children's Children? I think not!
@mellors- Radiohead has used it twice, both times in OK Computer, The Beatles used it a bit, especially on Magical Mystery Tour, Floyd barely used one, yeah, and RHCP used it on one song, I forget which. It was a big hit, which is why it's so popular here. Anyway. 'Tron = The best instrument ever.