Rancho Santa Margarita: has a lot of newer homes in the area, build in 2000 and up and sell hot. Some communities with about $60 for the second HOA gets you these extra amenities, http://www.samlarc.org/Amenities/Default.aspx?fiid=1114.
Irvine: has great schools and known for plenty of parks. HOA fees can last 40years and high, the rules can be very strict in exchange for a clean and upscale environment. Lots of great mid-high end restaurants. Very urbanized. Your shopping paradise include the upscale South Coast Plaza and Fashion Island.
In SD county, you best bet are along the coast from Oceanside to La Jolla. For more food and upscale shopping, stay closer towards La Jolla, particularly La Jolla Village. SD is becoming the new gastronomy with its annual food and wind festival and two other food festival weeks. Further north, Encinitas and Carlsbad have an array of great food and boutiques, Carlsbad has the Carlsbad Village. Oceanside, less upscale but the Arrowood community is in the great school district, with homes on the hill peaked between high $800k-$1m are now selling for $550k, 4200sqft, golf course community, great ocean breeze, you probably don't even need an air conditioner. There's no traffic issue (which is common in the southern part of SD county and Orange county) to get to the Carlsbad Village.
There are so many great cities in Orange and San Diego counties with the local pros and cons too large to list down. If you are interested, give me a call or email me, I certainly can help you narrow down.