Crucial Ballistix 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 1000 = 189$ after rebate!!!!

Crucial Ballistix 2GB (1GBx2) DDR2-800 PC2-6400 = 219$ no rebate

G.Skill HZ DDR2 800

^^^
Which of theses would you get and why? If not on the list I have up to $240 to spend on ram.