I am not a frequent flier, certainly not by standards of this site. Some years I make Silver, some not. So I clearly have to focus my travel.

I live in San Antonio. So far, I've been able to concentrate on NW/CO/DL. When I was silver on NW a few years ago I usually got upgraded. In reading another thread on this forum, most posters said that UA and AA miles were the best to have. My boss, who is an AA million-miler, said he's never paid more than 25K for a ticket (we're talking domestic coach of course), while I often pay more than that on NW and especially DL.

Any thoughts on whether I'm better off being silver on NW (with upgrade privilages on CO as well) or AA? Have upgrade chances gone down enough in the past few years to make silver on NW not worthwhile, so that I should go for the AA miles?

While I'm not exactly in your shoes, I am in that I sometimes make Silver on NWA and sometimes not (sometimes just on CO or United or AA or what have you).

I am happiest with my elite status on NWA, because it (and CO) are the only airlines which allow you to elite automatic upgrade for free. I have seen my upgrade percentages decrease, but it still is by far the biggest perk in the program for me (along with early borading).

I have a lot of trouble redeeming my NW miles, but I assume that if you live outside of a hub it might be easier for you. I would not recommend using miles for domestic flights, but thats just me.

What about the complimentary elite upgrades on US? Even Silvers have access to those, they're valid on any Y-cabin fare, and they clear at the 2 day window for the Silvers.