DDR2 Standard?

Which motherboard is that? It probably says that it will support DDR2 upto this speed (1200 MHz), so no, you just need DDR2.
 
considering that there actually isn't a standard for DDR2 1200 ...

I'm guessing that it's an nF680i based board with EPP/SLI ready memory support.
 
Depends on the processor. A typical Conroe runs DDR2 at 266 MHz and thus requires DDR2 533 memory. Overclock the FSB and you need faster RAM. The E4xxx systems use a 200 MHz FSB and only need DDR2 400. If you get something more modern, the requirements go up. Overclocking raises the bar substantially. AMD AM2 systems work best with DDR2 800. Your mileage may vary...