N86 would be priced around $400 , that translates to around 22k ,(comparing with other nokia at that price). Nokia is too late in 8 mp market and they cant afford to price it much higher . N86 also supposed to have better build quality , thanks to metallic accent. It also just won the best camera phone award from tipa.that does say something.
Samsun omnia is good phone , but putting windows on it kills it. There's reason why new omnia is based on symbian.It is good in spec sheet , but is actually just another winmo.slow and battery hungrt.
As far your requirment are concerned , nokia 5800 fits perfectly , so if you like it , then just go for it. I'm using this phone (with ep630) for past one month and it rocks in music. Battery in music is and 640x360 screen cant be beat for its price.