This isn't exactly a forum per se, but I often drop in on a style blog that has plenty of discussion, called "Une Femme d'un Certain Age". It's run by a California woman who has a definite interesting point of view about fashion, especially for women from 40 to infinity!
Her style is more California-edgy, I would say, but I like her choices for her, except her strong proclivity for black clothing. She's a great writer, and her modeling of various looks is well-photographed and artful.
The only other forum I'm regularly on is the "Faithlife" groups. It's a great umbrella site for those interested in various theological subjects.
Oh, and I'm constantly checking the "Hugh Hewitt" site for keen political analysis...