Open Question: which comp is better for gaming?

i was wondering which comp would be better for gaming and which will keep up with the latest game in the future? Intel® Core™ i7-920 processor(8MB L3 Cache, 2.66GHz) 8GB Dual Channel DDR3 SDRAM at 1066MHz - 4 DIMMs 500GB 7200 RPM SATA Hard Drive ATI Radeon HD 5870 1GB GDDR5 Dell 1525 Wireless-N PCIe Card OR Intel® Core™ i5-750 processor(8MB Cache, 2.66GHz) 6GB Dual Channel DDR3 SDRAM at 1333MHz - 4 DIMMs ATI Radeon HD 5770 1024MB GDDR5 500GB - 7200RPM, SATA 3.0Gb/s, 16MB Cache