Need good speakers to listen to music

Hi I need good speakers to listen to music.
I think about these speakers:
Z506 5.1 Speaker System
Do they good for listening to flac music?
Would I see difference with those speakers when I listen the same music in flac and mp3?
Some info about them:
Official Site: http://www.logitech.com/en-us/speakers-audio/home-pc-speakers/devices/7191
Review: http://www.expertreviews.co.uk/pc-speakers/1281868/logitech-z506

Answer #1
I’ve got the Logitech z5500’s they are awesome, better than my home cinema setup.
http://reviews.cnet.com/pc-speakers/logitech-z-5500/4505-3179_7-31115626.html
They have really dropped in price too, can get for around £250 in the UK now
*edit – the sub-woofer is really big though, takes up a lot of space.
*edit 2 – forgot to say I use em with a Creative SB Xi-Fi Xtreme Music card, and also use the optical in connection quite a bit.
Answer #2
Are you gonna use em with your onboard audio or a dedicated sound card? This can make a big difference,If your gonna invest
in quality speakers,You should also invest in a dedicated sound card.
Answer #3
Logitech is crap and that’s the end of it.
Answer #4
Logitech X-540’s are decent.
Answer #5
I got Logitech Z-2300 (200W Total Power) 2.0
Answer #6
How much are you willing to spend?
Are the speakers going to be sitting on your desk? If so a 2.1 set will be your best bet…
A great site I used to decide on getting my Corsair SP2500’s:
http://www.best2.1speakers.co.uk/