You probably have too many options, but here's my two cents.
Renaud's is definitely a winner. Scarlet Begonia is new, and also above average. But don't spend all your time on State Street. Two options on the beach are the Boathouse and East Beach Grill, I prefer East Beach and it's good for breakfast or lunch.
Breakfast at Renaud's or Crushcakes is a good idea, as others have said. I really enjoyed Crushcakes' lunch as well. The croque monsieur at Renaud's was fantastic, and you can't go wrong with a cupcake... (Hmm, I didn't mean to imply Crush Cafe was only cupcakes. They have good sandwiches and salads!)
Norton's Deli has great pastrami sandwiches--that's a hearty lunch for you. They may only be open during weekdays.
Tupelo Junction has good breakfast and lunch food, and they're extremely well-located on State Street for people-watching. They have eclectic but good food. The breakfast beignets are delicious, the scrambles are tasty, and they have good French toast.
Esau's is also a good/fun place for breakfast and lunch, though it there is usually a line out the door!
for breakfast: renaulds (for the most amazing omlets in town), d'angelos and scarlett begonia.
for lunch: paradise cafe for atmosphere, adama for heathy vegan food, carlitos for mexican with a fun patio, SBshellfish co at the end of stearns wharf for seafood or ca dario for fancy italian. have fun!!
For breakfast we really like Crushcakes on Anacapa and Jeanine's in Montecito on Coast village road has great food and great people watching! Lunch at La Superica on Milpas is a must. Try some of the specials (chili rellenos, enchiladas and chilquiles are especially delish) and #16 Superica special. We also like sitting outside at Pierre LaFonds in Montecito-they have a good salad bar and sandwiches to order. Added bonus of getting to browse the clothing and housewares that is part of the complex. Also good people watching and lots of Montecito locals.
Breakfast at Anderson's Danish Bakery and Cafe in downtown Santa Barbara on a sunny morning is a favorite for their charming sidewalk tables under the arcade and people watching as well as their food. Recent posters found Jeannine's muffin cafes (in several locations) to be very tasty. Renaud's in two locations is superb for their very French croissants and other more hearty breakfast selections. Eggs Benedict gets special mention at the Crocodile in the unlikely Lemon Tree Inn location. Nearby Las Aves Cafe also in the Encina Lodge motel near Cottage Hospital is another good breakfast choice.
My own lunch favorite is the truly fabulous Antipasto Assortiti appetizer plate (don't share!) at Ca Dario and finishing with a Affogato for dessert if you are downtown. Try not to miss either La Superica Taqueira on Milpas for lunch - my favorite is the Number 15 Special - but there is a lot to chose or if the lines are too long, El Bajio has an equal number of fans a few blocks away. I also like the lighter menu items at Saigon In and Out on State Street. for Viet-namese fresh spring rolls. The Boathouse at Henry's Beach (Arroyo Burro Beach) has some very well priced happy hour specials after 3pm, depending on when you are going out to dinner. The Art Museum Cafe has a good tapas selection now.
Petit Valentin in La Aracada off State Street downtown is a lovely setting choice. And while i have not been there, Scarlett Begonia in Victoria Court, also downtown, is getting some very nice reviews for both breakfast and lunch.
It is Summerland (not Summerville) and lunch at The Nugget and their crunch burger is always a hearty choice. Or try the power-lunch spot in Montecito - Tre Lune. Further down the road are some great choices in Carpinteria - small town, wander and see what appeals to you. I particularly like Giann-Franco but not sure if they are open for lunch. Even further down the road for an extraordinary setting, but more okay food is the Shoals Restaurant in the Cliff House Inn in La Conchitas - best oceanside dining setting on the coast- once you enter their pool side patio area you feel you are world away with the sweeping vista, crashing waves and palm trees.
If you are here midweek there is a Gourmet Dining Room for lunch daily at Santa Barbara City College near the beach run by the students of the Culinary Arts Department that takes you on to this campus with its stunning city views and overlooks. Call the campus for reservations.
There are hundreds of choices in this town for breakfast and lunch so I have only hit a very few of my own favorites. Other posters will have plenty more to add as well. You almost can't go wrong where ever you end up for either breakfast or lunch in this town. Dinner is where things shake down a bit but while there are only a few really top tier dinner choices, there are plenty of really wonderful choices all over town almost everywhere you look.