Gaming PC Rig

I'm building a gaming PC, hoping for it to last me years to come. Cut to the chase, is this sufficient to run the latest games on ultra and games in the future?

* Intel 3rd Generation Core i5-3570K
* AMD Radeon HD 6870
* Corsair CMZ8GX3M2A1600C​9B 8GB 1600Mhz CL9 DDR3 Vengeance Memory
* Powercool 750W 80+ Dual 12V V2.2 High Efficiency PSU
* Seagate Momentus 2.5 inch XT ST95005620AS 500GB 7200rpm Internal Hard Drive
* Gigabyte GA-Z77X-UP5-TH

Also, how many hybrid HDD will the PSU be able to power before needing an upgrade on the wattage?

- Thanks.