This is a very good question, especially if you are looking at buying rental houses in far flung Riverside County where houses are super cheap right now. Will people still rent in Hemet, Victorville, Temecula, Menifee, Desert Hot Springs with $6 a gallon gas? Will high gas prices depress rents?
That is a good point about poor people moving out of inner cities to suburbs in CA too. I know that a lot of lower income folks have moved out of LA to places like Moreno Valley, Victorville, Perris, etc… probably b/c of the lower rents and less crime (less crime for now at least). The whole idea that ghetto areas are more likely in inner cities has changed with the low income migrations out to Riverside and San Benardino Counties (and Lancaster/Palmdale part of LA County too).