I second all of that. Leftoverture for the album where it all came together, as far as I'm concerned; Point of Know Return for what they did next, which is still awesome and even takes a few new chances; and Song for America for the earlier sound, slightly more proggy in some ways but also showing other sides of the band that got left behind a bit. Same lineup, same six guys. And the live album Two for the Show is also great, but I would wait until you're more familiar with the studio versions, which IMO are generally superior. Their music can be intricate and layered, and we lose some of that on the live album. It's made up for with the energy of live performance, and it's a great album (especially the newer 2-CD version, as mentioned), but I don't go back to it very often. I consider it a "fans only" kind of release, and I generally love a good live album.