Don't know about LA but my FAVORITE place to get a souffle in new york city is at Jean Georges for lunch. At LEAST a day in advance you have to call to pre order one but you can order ANY flavor you want. The pastry chef makes them all himself and as long as they can get the ingredients he can make it.
He makes the best souffle i've ever had.
Sadly, the Moustache Cafe in Westwood Village has been gone about a year now and is being replaced by "Sushi Go-Round". I peered thru their window last week, and yes they're building a round conveyor belt contraption. I await their opening with NO enthusiasm or expectations of anything noteworthy.
Not sure if you are going to be in the Orange County area, but Mr. Stox in Anaheim has wonderful sweet souffles. They actually pour a warm sauce over the souffle just before presenting it to you... a light raspberry liquid over the raspberry souffle and a rich fudge sauce over the chocolate souffle. Both are served with real, fresh whipped cream. Haven't tried the Grand Marnier.
Also, the souffles at Off Vine in Hollywood are really good. A couple years ago they had a pumpkin souffle during the fall. However, its hard for me to order any dessert other than the banana cream pie there...
Bistro de l'Hermitage, a casual French in Culver City, often has a really lovely, deep, not overdone chocolate souffle as a special frequently - you have to let them know before the meal that it's what you'll be wanting as a dessert because, you know, it takes time to make. Lovely restaurant, not overly fussy, outdoor patio on a broad, pretty sidewalk, the kind of place you could go with a date, your mom or alone.
Start here for the pics:
Then go here for the menu:
9727 Culver Boulevard
Culver City, CA 90232
Phone: (310) 815-8222
Fax: (310) 815-1221
A quick search on this board will help you create an extensive list. But, to help you start off --
Hotel Bel Air (Bel air souffle)
Arroyo Chophouse (recommend the Grand Marnier one)
Smaller, decadent souffles:
Grand Lux Cafe