Not retired yet, but downshifted to part-time. I have been giving this some thought.
I already live in a pretty good location in the mountain suburbs of San Jose. Pretty high quality of life (restaurants, health care, cultural stuff, etc). Weather is pretty good: mid 70s almost year round (gets to low 80s in March and April), rainy season can be a drag (3 months of 60% of afternoon shower, 3 months of 95% chance of sustained afternoon shower). Beach is 1.5 hours away. Have thought about downsizing our house, but while we're currently empty nesters there's a non-zero chance my second son moves back after college; also my FIL spends about three months of the year with us (would definitely not want to be in tighter quarters in that situation. Our home is totally paid for and we really enjoy our hood (great place for morning walks).
My parents are in their 80s and I'm the only sibling living locally. It's a treasure to have them close by; haven't really entertained the thought of moving away while they're alive. We have given thought to spending chunks of time in other locations. Some places we have considered are Spain (Valencia and Madrid), NC, and Miami (though the US is probably out for the next few years).