I have 3.6s, but also had smga's and 2.somethings, here are some comments:
Dark Side of the Moon - absolutely amazing. 'Time' is better than most speakers because of the way things flow from maggies. You will do well with all of the Floyd stuff.
LedZep, Whole Lotta Love - this is an example of a fairly well recorded 70's song, sounds awesome! And the 3.6s at least have plenty of grunt for the grunty sections.
Rush - old stuff - sounds horrible! Very flat and 2 dimensional. I got the 'gold' recent re-release and compression is so high I prefer the original CDs I bought in early 80s! As they got older the recordings got better. Moving Pictures closed the 70s (1981) and it is pretty good, but I still feel a sense of flatness. When I listened to my Rush 'tapes' back in the day I remember always trying to get more out of them via tone controls and never quite making it work.
Fleetwood Mac - well you know how female vocals do on Maggies!
Early Ronny James Dio - pretty moderate/low, but when it is just him singing great, late Dio, darn good.
If you get into some of the rock that is less clean, when they have 3 or 4 guitar players, it kind of sounds... annoying. You can really hear all of what looking back may seem like noise. On the other hand, some stuff that in my memory is a bit 'muddled' like Hendrix for example, cleans up really well on modern stuff - instruments and people separate, there is more music and less 'noise' if that makes sense. I honestly feel more connected on good equipment.
I'd say go for it if you like some of the cleaner stuff, also don't know if you are more on the softer or harder side - if on the softer side (which can potentially include Simon and Garfunkel although technically that is folk, no?) that comes out awesome.
If you want to rock out to bands with all the 'rythm guitar' players added to the standard 3 or 4 person band, then I actually like the horn idea above. Kilpsch does some interesting horn stuff that isn't super exotic or expensive.
Best way to find out - take your 10 favourite CDs to a local dealer and try them on the 1.6s! Try Whole Lotta Love and Time - you'll be blown away!!!