She will love this. But include a gift receipt just in case. She might just want an excuse to go shopping.
Classics like candy, flowers, and jewelry are classic for a reason: They Work. Especially if you give all three. DO NOT forget the card.
Food.
What's her favorite candy? Favorite restaurant? Favorite meal you can cook?
A Love Letter if appropriate.
You might think she's not into that stuff but guess what, she is. It doesn't have to rhyme or be corny; you can even make a Top 3 Reasons I Love You list. Make sure at least one is really schmaltzy.
Digital Picture Frame.
You can pick one up at Target or Costco and pre-load it with photos the two of you. It's personal, functional, refillable, adorable!
Dishes.
Yes, dishes. If she likes to cook and/or entertain, pop over to your local Crate & Barrel, Pottery Barn, or Sur La Table and pick up a pretty serving dish. Those are the kind of things she probably loves when she passes by them but never splurges on for herself.
Candles.
One of the more cliche gift ideas for women but honestly, the ladies like them. But not just any candle: A ridiculously expensive soy candle that "burns clean" (no soot in the air) and smells wonderful. She will enjoy it many times and think of you. My favorite is Votivo Red Currant.
Take her to lunch.
But not just any lunch. Do these 4 things--
Pick her favorite place. It's surprising how many people take their friends to their OWN favorite restaurants. If she likes Chili's, darnit, go to Chili's.
Invite a couple other "surprise" guests. Having extra people there makes lunch more festive.
If it's a special occasion, tell the waiter ahead of time to bring a treat after the meal. It's a nice touch.
If it's not too last minute and you have time, stop by the grocery store and pick up a card and a single mylar balloon to match the occasion. It's fun to embarrass your friend by making her drag a balloon around.
Spa day.
As far as gift ideas for women go, this is an oldie but a goodie. If you have a great day-spa near you, treat her to whatever you can afford and if you're female too, bring yourself along for girl-talk.
Even if you don't have a swanky spa there is surely a nail salon nearby. Swing by Starbucks on the way and pick up some iced Lattes, then get adjoining chairs for mani/pedi treatments.
Mini Makeover.
Again, this is one of those gift ideas for women that works best if you are woman as well. Schedule a consultation at Sephora or any cosmetics counter. Ask them to do a smokey eye or whatever the latest trend is and take before and after pictures. Then give her a giftcard so she can buy the products she liked.
A Swanky Accessory.
At any department store that sells high-end bags like Coach or Dooney & Bourke, you'll find smaller items like keychains or change purses which are just as chi chi and much more afforable than the big bags. This cute Coach picture frame key fob is only $28. But if you can afford the big bag, go for it.
Balloons.
I dare you NOT to smile when someone approaches you with a bunch of balloons.
The grocery store is your friend again here. Pick out 1 fancy mylar balloon with a cute birthday theme, add 6 more regular balloons in complementary colors, add helium and a ribbon and you're all set.
Pajamas
People don't normally buy themselves pajamas, or if they do it doesn't happen as often as say, sweaters and pants. So getting a new soft pair of PJ's can be a fun unexpected treat. You don't have to worry much about sizes either because with sleep attire, bigger is usually better.
If you have time to order online, see Sleepyheads.com. They offer all the hip brands you've probably never heard of but she has.
Coffee
Probably one of my less original gift ideas for women but I make it because it's safe, it's appreciated, and if you pair it with an unusual mug or homemade biscotti it's a well-rounded, thoughtful gift.
My favorite is Peet's. It's strong and they do nice gift packages.
She will love this. But include a gift receipt just in case. She might just want an excuse to go shopping.
What's her favorite candy? Favorite restaurant? Favorite meal you can cook? 
Yes, dishes. If she likes to cook and/or entertain, pop over to your local Crate & Barrel, Pottery Barn, or Sur La Table and pick up a pretty serving dish. Those are the kind of things she probably loves when she passes by them but never splurges on for herself.
One of the more cliche gift ideas for women but honestly, the ladies like them. But not just any candle: A ridiculously expensive soy candle that "burns clean" (no soot in the air) and smells wonderful. She will enjoy it many times and think of you. My favorite is Votivo Red Currant.
As far as gift ideas for women go, this is an oldie but a goodie. If you have a great day-spa near you, treat her to whatever you can afford and if you're female too, bring yourself along for girl-talk.
Again, this is one of those gift ideas for women that works best if you are woman as well. Schedule a consultation at Sephora or any cosmetics counter. Ask them to do a smokey eye or whatever the latest trend is and take before and after pictures. Then give her a giftcard so she can buy the products she liked.
At any department store that sells high-end bags like Coach or Dooney & Bourke, you'll find smaller items like keychains or change purses which are just as chi chi and much more afforable than the big bags. This cute Coach picture frame key fob is only $28. But if you can afford the big bag, go for it.
I dare you NOT to smile when someone approaches you with a bunch of balloons. 
Probably one of my less original gift ideas for women but I make it because it's safe, it's appreciated, and if you pair it with an unusual mug or homemade biscotti it's a well-rounded, thoughtful gift. 