Thanks for your purchase - lots of fun awaits you!
For cables, choose a speaker wire that is appropriate gauge for the distance you are running (typically 14 gauge for most situations) and make sure it is speaker wire specifically, not lamp cord. Speaker wire from companies like Monster or Tributaries or Kimber or Audioquest are all good and have affordable options. A subwoofer interconnect cable from any of these brands would be fine too. Banana Plugs allow for easy connection and disconnection - good for store and studio demo rooms, not necessary for a home system (typically can't be used with wall mounting anyway).
The 3's include a simple keyhole mount for on-wall mounting, as well as a 1/4-20 threaded insert for use with a universal swivel-type bracket. There are many good receiver brands to choose from - a few of the more popular ones are: Anthem, Arcam, Integra, Marantz, NAD. Your GoldenEar dealer should be able to provide assistance with all of these items.
Enjoy your new system!