Welcome!
Questions for you:
1.) Budget?
2.) The given space?
3.) Uses (audio only, HT, or both)?
4.) Your tastes?
5.) Desired source(s)?
Being retired myself, have an idea of what constitutes a "retirement system" might look like: smaller, simpler, reliable, not a ton of bass, highs, or output needed, and perhaps low budget. Thankfully the lower cost end of the scale has never offered better value. Leading that promise is CD quality streaming ($20/month or less for access to millions of albums that are completely portable with storage issues). Which would require some sort of streamer/DAC. NAD (celebrating their 50th anniversary) offers $550 Node 2i, a $1650 C658 (a "Node on steroids"), or the $2750 M10 (from their Masters series which includes 100 wpc amp). All operate off BlueSound and can be controlled via Windows, Mac, Android, or iOS.
Another smaller/simpler option is the use of active monitors (way better performance per cubic foot and dollar). Actives use a low voltage crossover to feed one channel of amplification per driver for technically and sonically superior performance. Prices start at $300/pair for JBL 305 Mk2 (another company with deep roots) and go up from there. We can talk when you compile 3 or more posts.
