In fact you need an amp for the hd 650, so it's more expensive at the end.
"Best" depends in fact of your musical tastes. I'd say the hd595 shine for anything relaxing (classical, chill out, ambient , katie melua etc ..).
If you are looking for some "excitement" you might be a bit frustrated (not everyone agree, but you notice the number of people that say that these headphone are boring).
Look at the ath m50 for instance, they are said to be good value (just a suggestion among others, do some search).