Yes, the 7970 is AMD's best single GPU card. Faster than the GTX680 and still $100 cheaper. Nvidia tends to have a little better driver support but that will change with the next gen consoles since both will be AMD-based. So basically all games will be built on AMD hardware for the next 6 or 7 years at least.
Core i5 2500K @ 4.8 GHz || 16 GBs 1600 MHz DDR3 || Sapphire Radeon HD 7970 || Dual 128 GB SSDs