Unless you upgrade your speakers IMO the Rotel or the NAD alike will be sufficient enough for your current speakers.
There are many good cables out there. Audioquest, Transparent, Kimber Cable, Nordost, Shunyata Research, Chord Cable to name a few.
The Shunyata Venom, which is an entry level model from Shunyata, are awesome for the money. For your setup, I would look for a Shunyata Venom HC power cable, speaker cables and XLR cables. For USB, I would look for a Transparent Premium or an Audioquest Vodka or higher.
There are many good cables out there. Audioquest, Transparent, Kimber Cable, Nordost, Shunyata Research, Chord Cable to name a few.
The Shunyata Venom, which is an entry level model from Shunyata, are awesome for the money. For your setup, I would look for a Shunyata Venom HC power cable, speaker cables and XLR cables. For USB, I would look for a Transparent Premium or an Audioquest Vodka or higher.