Depends how much you are paying for it, since different companies charge different amounts.
But IMO the Dominator RAM is way overpriced, as you can buy mid-ranged RAM and overclock it to beyond that. I bought a fairly cheap set of Patriot DDR2-667 RAM, and overclocked it to DDR2-920, with timings of 5-5-5-15. Thats better then the Dominator DDR2-800 stock.