Fun and light? I would definitely read Emily Giffin's "Something Borrowed". It is so entertaining, takes place in Manhattan, and there is a sequel that, as soon as you're done with this one, you'll be dying to read!
If you like Christian chick lit there are ton of authors: Laura Jensen Walker, Camy Tang, Erynn Mangum, Kristin Billerbeck, Christa Ann Banister, Trish Perry, Rachel Hauck. lol too many to name. Let me know if you need more names.
I enjoyed The Undomestic Goddess by Sophie Kinsella- a fun & light read. If you like dogs and chic lit, try Finding Mr. Right by Emily Carmichael.... it is a hoot ...
A Hopeless Romantic by Harriet Evans!!! I was surprised by it, and have been recommending it to my friends. Several friends called me later to curse me out for recommending it because they stayed up all night reading. I also really enjoyed Mia King's novel Good Things, which has a protagonist that is a little older and more established, professionally speaking. I've reviewed both novels on my blog at: One Literature Nut.
Here's one that I think definitely falls into this category, though it's called non-fiction. I say "called" because, though I had assurances of the author that it's true and I feel bad to have doubts, it's such a hard-to-believe story. But I loved it! It's called Someday My Prince Will Come by Miss Jerramy Fine. If you read it, I'd be interested in hearing what you think. It's fluffy and has a sweetness and is much like what you might call a 'pull yourself up by the bootstraps fairy tale.' (If you're interested I have a Q&A with the author at my blog and a review, www.goodbooksbrightside.blogspot.com.)
Shannon Hale's Austenland was pretty good or even Confessions of a Jane Austen Addict...if you're into the Austen stuff.
Right now, I'm reading Confessions of a Prep School Mommy Handler by Wade Rouse. It's a memoir of a guy who worked in public relations for a prep school, obviously, but whose "real" job was to make rich, mean mommies happy. So far it's good. It's not exactly chic lit, but falls along the same lies...kind of like a guy's version of The Nanny Diaries.