Any suggestion on DAC below $1,500

If you can, pick up a factory refurbished NAD M51, usually ring at between $1,100-1,500.

Factory refurbished for the discounted price and same excellent quality, while maintaining a warranty when purchased through an authorized retailer.

I'll take the other side of this coin.   Eddy, I would tell you that the idea that you will hear a "big" difference between these dacs, even from $500 to $1500, is highly debatable.  You are welcome to go with what everyone is saying, but you should be prepared for the possibility that you don't hear much of a difference, or the difference is so small you'll wish you'd spent the money on something else.    Maybe there are huge differences between dacs that cost $300 and $10,000, I don't know because I've never heard a $10K dac.  But $1000 vs $1500?   Good luck with that.   I like Coli's suggestion of the Emotiva DC-1, or you could go with a Peachtree Dac-itx for $300 (I have one), the Schiit Bifrost is a nice unit and you can get the multi-bit version for under $600.   Tons of great choices well under $1000, even under $600.   

USB A-B cable from computer to DAC.
Is regular Belkin 15 ft cable would be ok? Or need to be a better cable.

Thank you,

Here is the cable.   

http://www.ebay.com/itm/NEW-BELKIN-F3U133-06-GLD-USB2-HI-SPEED-CABLE-GOLD-SERIES-6FT/111878549654?_t...