What's a great gift for my girlfriend's birthday, based on...?

I usually go here for anyone I'm looking to get a personal gift for.

http://www.etsy.com/

It's a community of artists and some of the stuff people sell on their is just incredibly beautiful. There are also a lot of very talented people who will do customizations for you.

Type phoenix into the search section there, or if you want to get her a piece of jewelery you could browse until you find someone who makes things that are her taste and then ask them to do a custom piece. I had a piece customised for my mum a few years ago and was amazed how precisely they made what I wanted.

Here are a few listings (I can never resist an excuse to browse this site)

http://www.etsy.com/listing/43803234/sale-phoenix-...

http://www.etsy.com/listing/46567844/light-and-dar...

http://www.etsy.com/listing/46948098/luxury-sterli...

http://www.etsy.com/listing/53516890/exquisite-han...

For a really unique and different birthday gift, have a look at a personalized Photo Collage Jigsaw Puzzle. Just send a selection of photos and specify any other hobbies or favorites she may have. 15-25 photos usually works best. You can also specify any words that you want - a message of favorite poem. Based on your photos and input, the professional designers will create a unique photo collage layout for your approval before making it into a puzzle. Don't worry, you get a chance to review and approve the photo collage design before they make a puzzle. Once completed, it can be framed and put on the wall as a keepsake of the birthday.

A poster. Go to the phoenix rising site and they have some sweet ones. Poems too, if you want to get mushy! A hand full of daisies and a milk shake date. LOVE!