I guess it also depends if you want to start something for fun or rather serious.
Check some of the big manufacturers homepages too, so you can see what specifications could
help the realisation of your ideas or set limits to them.
What helps for shure is if you choose a platform, that can be configured easily and its much more fun if you start with something that can work out of the box too.
Here an example, like you can find it on a lot of manufactureres homepages on the web.
http://www.toradex.com/En/Products/Colibri
Colibri modules feature state of the art technology, and aimed at low power systems that require high CPU performance. They are equipped withall the interfaces needed in a modern embedded device.
Colibri T20 features include:
· Dual Core ARM Cortex A9 Processor
· 2 x 1.0GHz Processor Speed
· Full HD 1080p Video (Encode / Decode)
· Powerful 3D Rendering Performance
· True Dual Display
· Up to 12 Megapixel Camera Sensor Support
And if this is to much there are Colibri modules in the family which are in a lower price range with adapted specifications that might fit you needs better.
What I personally think is important, that you know that you can get good support and talk to the right people in person as well.
Give it a shot and good luck.
Regards