Now, yes yes, i know this is a nigh on impossible question- but lets try anyway!- mine, i would have to say is Metropolis part 2- what you think?

Scenes From A Memory/Metropolis, Pt. 2, easily...

...everything they've done since has paled in comparison...their last two have been some of the most derivitive garbage I've ever heard...excellent playing as usual, but their compositions blatently ripp off everyone from Yes to Al Di Meola to Tool to Metallica...it's sad really...

...oh, and I really, really, really, wish they would kick James Labrie out of the band...

Heh he- my sentiments exactly- although i do enjoy six degrees- even though it does clearly rip of said bands