Spin Master makes a lot of cool, trendy toys like Bakugan, Tech Deck and Zoobles. My kids were really into Bakugan a few years ago, and I have to admit, I think they are pretty neat little engineering wonders. However, I think that Spin Master's greatest accomplishment in the last few years has been the production of the Liv doll.
Liv dolls are ~12-inch tall, highly articulated plastic dolls with changeable wigs and inset eyes. Several other doll companies have made mass-market play dolls with changeable wigs at this point, but as far as I know, Liv was the first girl on the block to have one. You can find Liv dolls at all of the big department stores for $15- $20. They are often on sale for less. Target, Walmart and Toys 'R' Us have had exclusive editions. FAO Schwarz carries them now, too.
There are 6 Liv characters; Sophie, Daniela, Alexis and Katie (the original four), Hayden (who joined in 2010) and Jake (the only guy so far). They all have different physical features, but I will talk about that later. Here is Katie from the "It's My Nature" wave: