First, I will assume that you are looking at an i7-7700K (unlocked multiplier) and not the plain i7-7700. Even without needing the unlocked multiplier for overclocking the K version has a 600MHz higher base clock speed.
The two boards you list are really different from one another. The Xpower is a well reviewed solid board with high overclocking potential and a pretty high price. This board is meant for significant/extreme overclocking. The D3 is a budget board with a few not so good user reviews. I actually went with neither of these boards in my build and instead chose the Asus PRIME Z270-A, good board with moderate overclocking capabilities.
http://www.trustedreviews.com/best-z270-motherboards_round-up
http://www.thebestgamingmotherboards.com/best-z270-motherboards
PCPartPicker part list:
https://uk.pcpartpicker.com/list/wNvB9W
Price breakdown by merchant: https://uk.pcpartpicker.com/list/wNvB9W/by_merchant/
CPU: Intel Core i7-7700K 4.2GHz Quad-Core Processor (£310.90 @ Alza)
CPU Cooler: Noctua NH-D14 65.0 CFM CPU Cooler (£64.25 @ CCL Computers)
Motherboard: Asus PRIME Z270-A ATX LGA1151 Motherboard (£140.90 @ CCL Computers)
Memory: Corsair Vengeance LPX 16GB (2 x 8GB) DDR4-3200 Memory (£119.59 @ Aria PC)
Storage: Crucial MX300 275GB M.2-2280 Solid State Drive (£89.99 @ Amazon UK)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£44.99 @ Novatech)
Video Card: MSI GeForce GTX 1070 8GB Video Card (£422.81 @ Ebuyer)
Case: Zalman ZM-Z9 NEO WH ATX Mid Tower Case (£55.99 @ Aria PC)
Power Supply: FSP Group Hydro G 650W 80+ Gold Certified Fully-Modular ATX Power Supply (£89.70 @ Amazon UK)
Optical Drive: Lite-On iHAS124-14 DVD/CD Writer (£12.99 @ Amazon UK)
Total: £1352.11
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-03-09 12:07 GMT+0000