It's The Wicker Man for me, no doubt - a perfect anthemic rocker and opener.
Be Quick (speed metal stuff is always cool), Futureal (same as the description above, essential Maiden) and Sign Of The Cross (those melodies) are on close second. Different World is right after them, such a melodic gem.
As for the others: Eternity is great (if only it had solos), Senjutsu is unique and epic, Tailgunner's structure is built to be an opener, Wildest Dreams is too simple and rock-y for the Reunion era, Final Frontier is nice (too long intro and repetition, they could have been a little more creative).