So what do you think I should get..

[kempa]

so i used to take piano lessons for a year back in 1992 and recently i felt the need to start playin some instrument again so imma go with the piano again

first i thought i'd get one of these:
http://www.uniquesquared.com/eBayImgs/yamaha_psr_e323_top.jpg




but after some digging i found out there's something called "midi master keyboard" or something like that, which i thought would be 10 times more useful than just a simple keyboard
im talking about the akai mpk 49 and the m-audio axiom 49

http://i291.photobucket.com/albums/ll302/Optimal-fx/ak-mpk49b.jpg

http://www.clavesound.com/osc/images/axiom49_f.jpg

so you audio boothas must know what these things are and what theyre capable of so i dont have to explain, right

so my question is:

should i get the axiom (which is about $200) or the mpk (about $400)
is there any significant difference?
the thing is i have never done a single beat in my life and i dont wanna spend $400 on something i may not use at all
..or should i just get a yamaha keyboard?
perhaps you can suggest something else? :{
im really lost here