I used to go to Palm Desert every year but have taken the past couple off. I'm heading back this October so my recommendations are from the perspective of a tourist. I love Cafe Des Beaux Arts on El Paseo I usually have at least one breakfast and one diner there.
I also have lunch at Las Casuellas Terraza a mexican place in Palm Srpings. There's a nice outdoor area for eating.
A fun place with interesting food (Hawaiian/Pan-Asian) (on 111 I think) is Haleiwa Joe's.
For an architecturally stunning building, great food and an even more spectacular view I would recommend Nepenthe in Big Sur. We had diner there at sunset on the deck high over the Pacific. It was stunning.
We're going to the Palm Springs area in October and it is one of our favorite places to visit. In Palm Springs itself there are many places right on the main road S. Palm Canyon Dr. that are good. Two that standout in my opinion are Las Casuelas Terraza a mexican place with a great patio area. The other is Kaiser Grill. Both places I've only had lunch. Another lunch spot was a place that I had lobster. Lobster might be in the name but I'm not sure. Something like the lobster hut maybe.
Just a short drive from Palm Spings on the 111 is Palm Desert and El Paseo a street with lots of art galleries and restaurants. I would highly recommend the Cafe Des Baux Arts. I've had breakfast, lunch and dinner there. We liked it so much we got to know the owner by the end of the week we were there.
The 111 corridor has lots of really good places to eat. There's a Roy's which was spectacular and there's a place called Halawea Joe's which is very good.
I'm looking forward to our trip and all the great food.