I always associate wine with warm and happy gatherings with friends as well as a fun way to explore one's palette (other than of course, food). One wine bar especially stands out, satisfying these ideals:
Gaffney's Wine Bar in Encinitas, CA (right off the coast highway, in the lumberyard plaza)
Unlike many wine bars that I have visited, the staff--Robert and Donna Gaffney, personalize your experience. Their passion for the wine they have in their store, shines through in their helpful suggestions and in knowledgable background they provide on each wine. The atmosphere is cozy--perfect for a meet-up with friends or a romantic rendevous. For those unfamiliar with wines and for winos alike, discovering the small production wineries that they feature is always a delight--expanding one's palette. They also have events such as dinner and wine pairings--where the chef from The Lodge at Torrey Pines comes in and prepares an inexpensive delicious meal and is paired with a variety of featured wines.
With the proliferation of winebars popping up everywhere with polite, but distant servers-- this "mom and pop" type of establishment is absolutely refreshing!
Another runner-up of mine, is Wine Steals---a nice, boisterous and fun place to enjoy wine with friends. However if you're looking for a more intimate experience--go for Gaffneys*