Newbie ?'s

I too like Steely Dan. A must have for any system that can rock is Jethro Tull's Living in the past. The MFSL set is by far the best you can get. Sonic Heaven !!!!!!

Frank Zappa is a-must for every guitar lover. Any of his albums are more than great. The well recorded ones are "Jazz From Hell", "Broadway", "Ship Arriving Too Late...".
King Crimson "Islands", "Discipline" and "Starless and Bible Black".
You can also "experiment" with Praxis' "Transmutation" which is Bill Laswell's project with the hell of the guitarist Buckethead. Excellent recording on Axiom CD with blend of heavy punk, funk, jazz.

for rock guitar:Robin Trower:Bridge of Sighs (remaster)

Given your stated tastes and the fact you don't mention vinyl in your new setup, I would second the recommendation for the recent reissue of King Crimson's "Discipline", as well as their live "USA" and "Red", all HDCD reissues. Lots of other good suggestions above as well.

You may also find Dream Theater's "Scenes from a Memory" and "Six Degrees of Inner Turbulence" good.

If you like instrumental rock and virtuoso players, I would highly recommend Liquid Tension Experiment (both Vol. 1 & 2), as well as Planet X's "Moon Babies".

Finally, when you need a break from the volume, I would offer Jane Monheit, "In the Sun", Trio Da Paz, "Cafe" (you'll have to google them to find their site), Peter Gabriel "4" reissue. A harder to find release, Mark Levine and The Latin Tinge, "Isla" is very well produced (especially for a small, local release).

Peter Gabriel "SO" Remastered is a must have IMO