Abhi,
My system (leaving alone the DAC is nearly finalized). I'd just replace the Polks with Aviano 2s. Having said that, I know the DAC would heavily influence the sound signature.
My preference if you ask me would be more around being able to feel the harmonics, the backstage symphonies (can't put it in some other words). The vocals is what I am primarily looking at. Slight less bass and slightly less sparkly highs would be fine but the vocals is what I die for.
I am mostly into acoustic tracks. Some cover tracks and hindi music. The vocals play a major part in my kind of listening. I know you'd probably suggest me to go the Vinyl way but I hate spending money every time I want to listen to a new track. I can stretch once but not every month. Also I've all my collection on my PC so there is not other good way to boost the experience than getting a decent DAC.