Um, bragging rights is when you have sli 590's. A 580 is not worth the extra 100 unless you plan on not upgrading for 2 1/2 years. Otherwise the 570 will suit all of your needs.
Unless you're doing 3DVS or 2560x1600 something, save some money and go for the 1.5GB 580. You'll see no real improvement from the extra VRAM on smaller resolutions.