My friend and I would like to celebrate our birthdays by meeting at a spa somewhere inbetween our homes (she's in Nevada City; I'm in Pasadena). We'd both like a nice hotel/resort with spa facilities and good dining either on site or close by. We'll probably go sometime in winter. If you have any suggestions, I would appreciate them very much. Thanks!

I've stayed at Two Bunch Palms and really enjoyed it. Also, the Marriott at Desert Hot Springs is beautiful and very upscale. Two Bunch is more isolated and low-key, but has natural hot springs and is like an oasis. Both are great in the winter.

www.rancholaspalmas.com
Rancho Las Palmas in Rancho Mirage is a wonderful resort. They have a spa, the pool is great, the breakfast buffet is delicious & 'The River', shopping & dining is across the street.
Have a wonderful time!

Since when is the Palm Desert area 1/2 way between Pasadena and Nevada City?

I'd be hard pressed to think of anyplace 1/2 way between the two of you, but think that Palm Springs or Palm Desert is a great idea for wintertime weather considerations.

We very much enjoyed the Ojai Valley Inn and Spa, but if you are not also golfers, you can run out of things to do there....can only afford so many massages at $100 each!

2 suggestions - La Quinta near Palm Springs is wonderful or, even better, the Golden Door Spa at The Boulders in Carefree Arizona if you are flying. The Boulders is incredible and the spa is fantastic.

I don't think that you'll find something in between that fits the requirements you list. You can however work it out if you fly into Sacramento and your Navada City friend picks you up and you go onto Sonoma for the weekend. Or your friend can fly into Burbank and you can pick her up and you can go to Palm Springs.