I just sold it to a local buyer for £800 so evidently was worth that as he offered it to jump the queue over another buyer... Don't forget in the UK add 20% onto everything that would be the cost in the US due to the taxes we pay at the point of sale (VAT) For example an antminer would be worth 20% more here than in the US for the same reason.
Breakdown:
Xonar Essence STX Sound Card: £100 - £120
2TB HDD: £50
3TB HDD: £80
256GB SSD: £70
Mobo: £100
PSU: £60
Blu-Ray Writer: £60
Nvidia GPU GTX 960: £120
i5 CPU : £120
Totals £720 at the current parts value online and yes I have checked.
So there is your answer
That is the current value of the parts individually, note this is an assembled machine and the sound card is a top of the line sound card.