Better ssd or better hdd?

Solution
If choosing between the two options and only those two options, I would select the 250GB SSD + 500GB HDD and get these:

PCPartPicker part list / Price breakdown by merchant

Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive ($107.99 @ B&H)
Storage: Western Digital Caviar Black 500GB 3.5" 7200RPM Internal Hard Drive ($61.99 @ Best Buy)
Total: $169.98
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-04-23 00:22 EDT-0400

Note that you just have to add $10.15 and you can get this:

Western Digital BLACK SERIES 1TB 3.5" 7200RPM Internal Hard Drive ($72.14 @ NCIX US)

...or even, save $12.10 and change the 500GB...
If choosing between the two options and only those two options, I would select the 250GB SSD + 500GB HDD and get these:

PCPartPicker part list / Price breakdown by merchant

Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive ($107.99 @ B&H)
Storage: Western Digital Caviar Black 500GB 3.5" 7200RPM Internal Hard Drive ($61.99 @ Best Buy)
Total: $169.98
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-04-23 00:22 EDT-0400

Note that you just have to add $10.15 and you can get this:

Western Digital BLACK SERIES 1TB 3.5" 7200RPM Internal Hard Drive ($72.14 @ NCIX US)

...or even, save $12.10 and change the 500GB Black HDD to this:

Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($49.89 @ OutletPC)
 
Solution