Hey Spalding, I'm in Temecula/Murrieta all the time. I've been through Corona, but couldn't really tell you about it, so I'll just tell you about what I do know.

Temecula/Murrieta is in southwest Riverside County, nestled between the rolling hills that seperate it from the coast (its probably only 30 miles by crow from the ocean) and the flatter expanse that continues north up the highways (called 15 & 215). Temecula (to the south) and Murrieta (to the north) have grown in a huge way in the past few years. There are a lot of great community parks, sports, events and resources. There are a lot of good shopping, dining and employment options. The public schools are comparatively excellent. It has good California weather, although it has hotter/cooler "extremes" (we're still talking California here) than on the more temperate coast. The housing prices have really started to come down lately, so there are some beautiful homes available at relatively more affordable prices than could be found even a year ago. (Although I would certainly move here and see everything before you buy anything). Also, because it grew rapidly, there can be major traffic congestion. Typically it takes about 2 minutes per mile to drive to a destination - but in bad traffic (or an accident) there is no limit to how long it can take. In general, I really like the area and think its generally safe.

Wow, I hope that's not too much info. Best of luck to you!