Lots of great posts on the best bits at TJ's but the woeful parking was also mentioned... Most locations feature nightmarish ingress/egress which tends to discourage frequent visits.
However, there is a relatively new location in Manhattan Beach - on Rosecrans between Sepulveda and Aviation - and it has oceans of easy parking. I go way out of my way just to shop there and it's well worth it! The store itself isn't nearly as cramped and cluttered as most and there always seems to be plenty of checkers.
Also, in the Woodland Hills area there is a TJ's in the Topanga Plaza mall. It's away from the big department stores and has a mall entrance nearby so it's a pretty easy in-and-out. On the downside, the aisles are cramped and dark and the place always seems to be mobbed.
Any other Trader Joe's locations that are particulalry noteworthy?