When it comes to unique, jazz-infused music, it doesn't get any better than Steely Dan.  Aja and The Royal Scam are the two "must-have" Dan CD's, in my opinion, although everything they have done is worth owning.  Their cool vibe is totally unique.  And although you wouldn't say they are the greatest singers out there, they are definitely one of the greatest bands to jam on stage.  There is just nobody else out there like Steely Dan.  I'm not a jazz fan typically.  I'm more into the classic rock scene; however, the first time I ever heard The Royal Scam album (my intro to Steely Dan), I was hooked.  That was nearly 3 decades ago now.  There is not a bad song on Aja.  My favorite tune on this CD is Black Cow, and it sounds as good today as it did the first time I heard it.  Will I ever tire of hearing Steely Dan?  I think not!