Recommend Media Player please

Hello

Could anyone recommend a media player please?

I would need to be able to connect via ethernet to my PC and then transfer movies onto the player so i can watch the movies without needing to turn the PC on

I think i would need 1tb of disk space on the player

Also it would need hdmi output and a nice UI is essential so myself, the missus and kids could use it without hassle

USB input would be useful too

My movie collection is made up of mostly avi and mkv but i also have mov files as well

I hope also that it would not have any 'sleep' mode so that once it is turned on it stays on so it is easily accessible

There are so many options that i think the UI would be the decider - we have a 'media streamer' that is connected to the PC but the UI is awful and causes a lot of moaning from the above list of family members :)

Any help would be gratefully appreciated

Best regards

Patrick

PS i am not interested in apple tv ;-)