Need some clarification please

Hey everyone, i've been out of the hardware trend recently and just need some help to refresh; got some questionsWhat socket do core 2 duos use? and what are the different intel trims? like what does QX and MX and stuff mean?What is the best bang for buck video card under $200US?DDR2-800 is the standard right now right? Is there any use for DDR3 RAM DIMMS yet?Thanks a lot guys, appreciate itNeed some clarification please
current core 2 duos and core core 2 quads use an LGA 775 socket ,ddr2 are standard now they are cheap,mainstream,have low latency thats why they are very fast and can pretty much run everything but the ddr2 bandwidth is limited to 1200,ddr3 starts from 1333 to 2000 and they are not backward compatible with ddr2 ram and they cost more than the double although the increase in performance is slight,but they are still under improvements.Until manufactures produce ddr3 with high bandwidth and low latency ,ddr2 remains a better bang for the buck Need some clarification please
[QUOTE=''Green_Scythe''] What is the best bang for buck video card under $200US?[/QUOTE]Radeon HD4850.