Sister's wants music system without the hassles!

Naim unitiqute.  Has amp, preamp, DAC, streaming, phono, and an app to control it.  30wpc.  I have one for sale on my local craigslist I’ll be happy to help you get if you want to go that route.  Currently listed for $775.  I’m in DC area.

lalitk, Yes, your recommendation is likely most suitable (minus the subwoofer perhaps). As I tell my wife "it doesn't cost anything to discuss it before spending the money". My suggestion is the only one of its type here, making it valid. And, it's easily the best bang for the buck. Aesthetics are certainly a concern. It's good to make note of that. Hopefully, all of our input will result in a nice little system for the lady. 

An inexpensive Outlaw receiver is excellent for the price and has everything you will ever need.

Those are very nice speakers, so assuming that your sister has been around your system and has good ears, but isn't an audiophile... there are a lot of good integrated amps out there. 
The speakers are 87db 4 ohm, so you will need something with a decent power supply and a minimum of 60 watts or so @ 4 ohms.  
Here are my thoughts off the top of my head, keeping in the Audiophile tradition.
Audio Refinement Complete
Classe Cap 101/Cap 151
Arcam Delta 290 Arcam 10
I'm sure that there is a Cambridge out there
Rega Brio 2 (if it'll handle 4 ohms) 
Old Krell (KAV 300/400)
Ton of stuff under $1000 that will do a good job. 
I'd look at something like an IFI Dac or Schiit Modi Multibit Dac or Audioquest Dragonfly red/black any of these would give her outstanding computer audio. 
She would be ready to go with a very satisfying system
I hope this helps,  Tim