Update
Well i'm no expert on this, but i decided to buy a ITX low budget board (afterall i only want to play music wth it).
Asrock E350M1, AMD A50M Fusion, CPU onboard, 2x DDR3, 4x SATA-600 (with HDMI) mostly i choose it for low power consumption.
be quiet! Pure Power L7, 300W (silent power suply)
Corsair, 4GB, PC3-8500 (DDR3-1066) (compatible with the mobo)
Crucial m4, 32GB, mSATA, SATA-600, SSD (silent SSd disk, i couldnt find a smaller one, and it was not that expensive)
All together for around 150 euro, a lot cheaper then the midi hifi set i had in mind first almost 60% cheaper.
But i think its more like how i want it, a computer can play music/video and can run a website to control it.
Next i'm planning for Linux and and some media center software, i've not done much with linux any tips are welcome 
Meanwhile i wonder if a arduino might be used to do button input (besides DLNA imput)..
However with arduino i have no experience writing code on linux to get things done it would be cool dough.