Nicole guest editor for Who What Wear

Nicole Richie is the September guest editor for Who What Wear.
The designer picked her must-have fashion and beauty staples for this fall.

Paul and Joe Folies Dress ($4300, 310.270.4620)
Leave it to Richie to find the perfect party dress! The green and white sequined swirls on the Folies Dress—which is part of the limited "Pierre Cardin pour Paul & Joe" collection—instantly puts us in a festive mood; it would be an ideal selection for any upcoming holiday soirees. "It's fun and a little baggy," Richie says. "You have the freedom to move around while still looking chic and elegant." That's a plus in our book! If you can't make the financial commitment to Richie's choice, See by Chloe's Sequin Mini Dress ($395) will give you an equally playful shimmer and comfortable loose fit.

Rebecca Taylor Cheetah Faux Fur Coat($995)
If you haven't already jumped on the leopard-print bandwagon, it's time to get going. Why, you ask? It's one of the season's hottest trends, looks amazing on your all your favorite items, and Richie loves it too! "Rebecca Taylor's plush faux fur coat is so soft and easy," Richie says, which makes it a top choice for her this fall. If you're still unsure about how to rock the feline print, you can always make note the way Richie incorporates it into her daily rotation: with jeans and a white t-shirt. If her exact selection is not in your price range, try Free People's About Town Faux Fur Coat ($198), which will look just as chic.

House of Harlow Mixed Media Cluster Ring ($109)
For House of Harlow 1960's Holiday 2010 collection, Richie incorporated a number of wintery materials into her unique designs. This ring, which is part of the Mixed Media Group, happens to be her favorite piece. "It's so fun and eclectic, and it even comes in a smaller size," Richie says, noting that not everyone wants to wear it on their middle finger as she does! Whatever size you pick, it's definitely a statement ring, thanks to its interesting leather-and-suede accents.

Spa Ritual Nail Polish ($10) in I Feel The Earth Move
We can always support a nail lacquer that is toxin-free, and if it has a long-lasting formula too, that's a very exciting bonus. Richie's polish pick possesses both qualities, which is why she gives the eco-friendly brand Spa Ritual two thumbs up. As for the color choice, she is particularly taken with I Feel The Earth Move—a deep chocolate hue. And although she says would like to be more adventurous with her nail colors, she typically gravitates towards red, black, and other gothic shades. "I tend to wear darker hues in the winter because this is time when I switch to lighter hair," Richie says. "I think it balances out the colors."

Winter Kate Adalia Bustier ($195)
There is something so appealing about those wardrobe pieces you can take from day to night without skipping a beat. Case in point: the black stretch bustier from Richie's own Winter Kate collection. Dress it down with a pair of light-wash jeans while running afternoon errands, then transition effortlessly into the twilight hours by switching into black skinny pants and a pair of heels. The latter is actually Richie's styling suggestion. "It's a great outfit if you don't want to wear a dress," she says.

Jerome Dreyfuss Carlos Bag ($936) in Rouge
In Richie's opinion (and ours too), no fall wardrobe is complete without a few great red pieces. Sure, there are plenty of ways to vamp up your wardrobe with this striking hue, but Richie prefers to give her all-noir ensembles a pop of color with a sexy red bag. Therefore, it comes as no surprise that she was immediately drawn to Jerome Dreyfuss' Carlos Bag; its cool, relaxed shape, and rich leather texture make it an ideal carryall for fall! If that doesn't fit your budget, we suggest Furla's Carmen Shopper Tote ($237) in Geranium, which emulates the Carlos' slouchy silhouette and sophistication, but with a more accessible price tag.

Helmut Lang Smoke Wash Grey Combo Jeans ($230)
When it comes to selecting the perfect pair of pants, Richie knows what she wants. "I look for stiffness and detail," Richie tells us, which explains her predilection for Helmut Lang's cool-yet-sturdy designs such as these Combo Jeans. Sure, black skinny jeans can be paired with just about everything, but these two-tone pants are definitely a more interesting and eye-catching choice for fall. "I like that they can go with a bunch of Winter Kate tops," Richie adds.

Alexander McQueen Studded Faithful Booties ($1285, 877.543.7463)
We have to agree with Richie's first thought after spotting these incredibly cool booties from Alexander McQueen—they're a must-buy—because frankly, we adore them too! Their luxuriously tough look would compliment a simple LBD perfectly, but they're sure to give any outfit the perfect amount of edge. They are an obsession-worthy pair indeed, but you can also try Iron Fist's Ruff Rider Booties ($43) to get a similarly edgy accent at a fraction of the cost.

Joe's Jeans The Ambre Tee ($72)
Fact: a basic white t-shirt is a must-have staple for every wardrobe. That said, we understand that searching for the most comfortable fit can sometimes be a daunting task. But fret not, dear readers, this linen burnout t-shirt from Joe's Jeans is the solution to all your problems—we promise! "It's super soft, but won't stretch out over time," says Richie, which is one of the things she likes best about this particular style. We second that!

Karen Walker Number Six Sunglasses ($170)
We happen to be big fans of Karen Walker's casual and effortless apparel and even greater enthusiasts of her quirky, modern eyewear. Richie shares a similar affection for the designer, specifically stating her appreciation for the Number Six Sunglasses. Richie fell head-over-heels for their round, sixties-inspired shape and sophisticated super-dark lenses, which is why they're her final pick for fall!
Two years ago, you may remember, she was the inaugural guest editor for WWW.