I mentioned earlier that I like to get things that we can use for our homeschooling as Christmas presents. I have found a couple of neat online stores where I do a lot of my Christmas (and birthday) shopping. I know that it is cutting it close for ordering online for Christmas, but figured that it could not hurt to mention.
Xump Science Toys
This is a perennial favorite. No matter how often I shop here, I always find something interesting and new (and I often find things for Jeff who is super hard to shop for!) They have tons of great ideas for stocking stuffers (the Pet Tornado was a big hit, we'll see how they enjoy the Pocket Volcano). It amazes me the range of cool science stuff they have...from kits for all ages and topics to lab supplies. Be sure to join their email list as they have incredible sales throughout the year.
Rainbow Resource is a terrific source of homeschool materials, but did you know that they are a great place to Christmas shop? Check out their 2008 Holiday and Gift Giving Catalog (you can download the pdf from their homepage if you did not get one). Tons of great educational and fun ideas. I do wish that the website was easier to navigate and browse...it is so huge that it is hard to know where to begin. But I have found that if I know what I am looking for, more often than not Rainbow Resource will have it.
Educational Innovations is a really neat science oriented online store. Tons of very unique and interesting ideas for any science lover. Also a great place to get those hard to find items for science experiments.
I also have a couple of additional websites I like on my Homeschool Shopping links page. Hope that you find the perfect gift!