The Pump Station! It's a breastfeeding boutique, and they also have a lot of neat baby items, good books, etc. There's one in Hollywood (on Vine at Fountain, in the strip mall with the Office Depot) and in Santa Monica (on Wilshire at... 25th? Near Douglas Park.)
If you're a size 2 and VERY fashionable, there's a maternity boutique on Melrose I've heard about. What I've heard about it is that they're really snooty with women who are already in a fragile hormonal emotional state. ;-) Sorry I can't recall the name (I never even went in there because I KNEW they didn't have my size just from looking through the window).
If you like art galleries and boutiques, Glendale Boulevard in Atwater Village might be a fun visit (mostly just the West side of the street though). There's a children's boutique called Mila that has adorable toys and clothes; the clothes are mostly by local designers. There's another boutique that is connected to the gallery next door, and features gifts and stuff by local artists.
Larchmont Village is a nice little afternoon also, again with the cute boutiques, and also with some good restaurants. I like the Avocado Grill.
The Whole Foods in West Hollywood has a separate space in the same shopping center called the Lifestyle store, so if you like the selection of clothes and accessories you often see in the Whole Body section, you might want to go there to browse a much larger sampling of it.
On Rowena near Hyperion, there's a store called All Shades of Green, which is an environmental consciousness boutique. ;-) All kinds of sustainably manufactured goods and so on. Not a huge selection, but kinda fun. Check out the dual-flush toilet in the back (yes, #1 and #2. ;-)
For a mall experience like no other, check out The Grove (at 3rd and Fairfax, next to the permanent Farmer's Market) or The Americana (in Glendale on Brand). Designed by the folks who maintain the "look" of Disney's Main Street. It just makes me feel all fuzzy to hang out there. ;-) The Grove has a more practical selection of stores, since The Americana is next door to the Glendale Galleria.