Mark:
Welcome to the group, and congratulations on your retirement. Yes, after 38 years, just get the best bike you want and don't compromise. Fortunately, any Rivendell model is a "bike you can grow old with" The designs allow a variety of set-ups, and it's easy to get the bars up high, so comfort is not an issue. Spend some time on the various photo groups & you will see a wide range of set-ups, bars, seats, racks, tires, etc. I believe Grant one time referred to a bike frame as a place to hang the parts you like to get the bike you want.
As to which model, think about what you want to do with the bike, and remember that the versatility allows you to do a lot of different things with the same bike. Do you want a "nice bike" to ramble around on? Do you know for sure you're going to load it down with 4 bags & take off on extended tours? Is your main interest off-road trails? It's amazing how just adding some racks or changing the tires can transform a bike.
When I bought my Atlantis 10 years ago, the model line-up was more limited than today. I knew for sure I was taking it touring and the Atlantis was the heaviest duty frame Riv made at the time. Rivendell had a wonderful brochure that showed Atlantis set up as touring bikes, commuters, mountain bikes, etc. So my choice was a lot easier than it would be today. I do 2 or 3 extended tours per year, but when I'm home the Atlantis is my go-to ride. To me, it's comfortable, stable and fun to ride off-road or on, loaded down or with minimal luggage.
My intention when buying my Atlantis was that I wouldn't be needing to buy any more bikes. While I am occasionally tempted by interesting looking bikes, a deep breath reminds me that the Atlantis does everything I need a bike to do. After 10 years and well over 40,000 miles, the two of us are aging nicely together.
dougP