Of all the albums you're discovered, which one gave the best first impression? Where does that album rank for you now? List multiple albums if you can't pick just one.
For me, my best first impressions, in order of when I first listened to them, are:
Ayreon - The Human Equation
Transatlantic - The Whirlwind
Haken - The Mountain
Spock's Beard - Snow
Dream Theater - The Astonishing
Of these, the Human Equation has aged the worst, probably top 50 but not top 20. As for the other three (not counting The Astonishing because it hasn't aged yet), they are all somewhere in my top 10, and I suspect The Astonishing will be too, though it's too early to say.