I went to a baby shower a few years ago at The T Room. It was very cute and girly. If you're having a girl this is a great venue. Very memorable.
I had a bridal shower at Cafe Bizou in Sherman Oaks.
Viva La pasta in Simi Valley has a nice outdoor area, as well.
have you looked at http://www.jinpatisserie.com/
it's not a private venue, but really pretty-right by venice beach