My 2 girls will be 9 and 11 at Xmas. I too am thinking of getting a furby for them to share. Not sure how much time they will spend on it as we are struggling to find time as it is. Have got them a camera each, will be getting them each a mini iPad type tablet/kindle Fire, and a clock/alarm iPod station.
As they are both into crafts, just bought them the Fashion Angels portfolio booklets, 3 lots each i.e. the fashion one, the interior design one and the hair and makeup book. www.amazon.co.uk/Fashion-Angels-Sketch-Portfolio-Triple/dp/B007Y3S7GK/ref=sr_1_36?s=kids&ie=UTF8&qid=1351204830&sr=1-36
Can get on Amazon but got directly from craftyarts.co.uk. Bumped up to £30 for free delivery. also will be getting them each 2 boxes of sequin arts again from Amazon. getting them also 2 boxes each of this woodcraft kit but in different styles. www.amazon.co.uk/Quay-P082-Carousel-Woodcraft-Construction/dp/B000640U3M/ref=sr_1_1?ie=UTF8&qid=1351204690&sr=8-1
Got them the Mystyle deluxe charm set as mentioned above last year with about 3 different sets of the friendship bracelet kits. Were nice but they are quite hard to make and time consuming. In the end, I had to finish it for them,only managed to make 2 for them. Still a couple of unopened boxes.
Still need to think of a few more smaller stuff including 3 annuals each, nail stuff, moshlings/puffles, CDs, stationery.
You could get them a nice jigsaw puzzle and a portable puzzle storage. My friends 12 yr old like puzzles but have trouble keeping the bits safe so I will be getting her that this year and she can just shove it under the sofa when she's had enough but no need to pack the pieces away.
My soon to be 9 yr old wants to learn knitting so I got her a chunky knitting kit from tkmaxx which has a 32 page booklet, chunky thick needles and chunky wool for £5.