Check out the latest (Fall 2006) issue of Vogue Knitting at your local craft store/B&N. There are some seriously cool new gadgets that she probably doesn’t already have since these are newnewnew : knitting needles that light up for knitting-in-the-dark, and a metal “sheath” holder thingy for double pointed needles WITH A PROJECT ON THEM!!! The Yarn Harlot blogged about receiving one of these at a signing awhile back. They aren’t just cases for DPNs, they will actually hold the needles with your sock (hat/mitten/whatever) dangling off of them. Invaluable for knitters who throw their project into their handbag and just go.
Alternatively, some unique beaded stitch markers (check out the buy/sell/swap forum; i believe someone here makes them…) would probably be well received. Oooh, also, you could look up a tutorial and make your own beaded stitch markers.
And of course, if you don’t already knit and crochet, asking her to teach you gets many brownie points. Most crafters love to share their craft.
And of course, if you DO already knit and crochet, making her something small but meaningful (tea cozy? iPod cozy? sweater for her dog? beaded lacy wrist cuffs?) will be well-received because she’ll know from experience how much effort you made.
Hope this helps!