My first purchases were two 3D model figures from a designer called Mr_Props. I ordered both of his Ersatz models (male and female). I've never bought a 3D model before and I have to say i'm pretty impressed.
They also make a beautiful 1/12 model that looks fiddly, but oh so tempting - but I figured this was a good way to start on their products and see if I like them.
I also ordered the hands set which are amazingly sculpted and full of character - well worth the small price.
But you should check out Shapeways. It's a great place for all kinds of creative awesomeness.