Artrage can be more interesting coz it feels a bit more "material" (it recreates the grain of the paper/canvas and stuff) and there are proper drawing tools implemented that interacts in a cool way. Photoshop is great too coz you can do wathever you want with it, potentially limitless stuff.I like to use both, artrage has layers and stuff and can export things in psd so you can work with both together.
yeah t&b, with a wacom bamboo fun A5 you can do a lot of stuff (that's what I'm using now) and is not too expensive, it has decent qualities and specs.
then you can try with a 21" cintiq hehe.
Weird fact: I like to put a paper sheet on the tablet surface, the pen works flawlessy and the "feeling" is much more "realistic" than drawing on the original smooth surface (even if it's studied to give the feedback of paper and stuff).