Same as a 5.1 surround system when watching a film.
Just invested in a 42" Plasma, AV amp and speaker system.
Always loved watching films but first film I watched on the new system and I was leaning down to get the remote off the coffee table when a gun shot rang out and I ducked.
SWIMBO almost fell off the sofa laughing
That would never have happened before and that is what I have been missing.
MP3 is great for what it is but you cannot beat HIFI quality for where it matters.
In the car, road noise, in the workshop machines getting used etc MP3 is perfect.
Sitting in the living room central to the front stereo speakers, different experience altogether.
The only choices are personal choice where you need to go to a HIFI shop who can demonstrate what you want to buy and your ears will tell you what sounds the best to you. Never mind how close it is to true rendition.
And, how far to go with the pursuit of "better" quality. Speaker wires, please don't use bell wire it does make a difference and doesn't cost much. Etc Etc