Thanks to all of you that have provided input.
Personally, I currently have a 7mm RM, a 7mm WSM, and a 7x57; the WSM is on hold pending a trade. My first centerfire rifle was a 7mm RM, and I have always held a bias toward this round. I enjoyed shooting the WSM, but there are other things that I want/ need, so it is an expendable asset. I will likely always have the 7x57, I like it that much.
I have no experience with the STW or Weatherby chamberings. Everything I've read indicates that there really is no appreciable advantage over the Remington Magnum, at least not for the type of hunting/ shooting that I'm involved in. I haven't fired a 7x61 or 7x64, and really haven't had much of an interest in either.
At times I have seriously considered adding a 280 Rem to my collection, and at other times a 7mm-08. Of course I have also considerd improved versions of both. In the end, I have always deduced that my Remington Magnum has always done exactly what I've required of it and the 280, desipte the laurels expressed by others, would be a backward step from the RM. The 7mm-08 also has a strong following that I cannot argue with. However, in my opinion, my eyes and ears are likely to fail me long before my knees and back will become a reason to switch to a rifle that is slightly lighter and shorter. So, the apparent advantages of the 7mm-08 over the 7x57 will likely not benefit me.
In some ways, this rationale is comforting, in others it is alarming. After all, it is nice to know that I have found merchandise that I am almost entirely happy with. Yet, formulating reasons to avoid trying new things seems contradictory to the idea of being a gun nut.