as I understand it, it's a tradoff... memory intesive proggies like tighter timings... but if you can offset that by increasing your overall cpu speed with looser timings it all equals out.
Ram is dependant upon budget... Hearing things like UTT will do 2,2,2,5 at 270 is great, but it's getting hard to get now.
My TCCD PDP xbl will do 300 2.3,4,3,5 so I'd say it's dependant upon what your processor can do, and what you would safely overclock it to.
at stock, any good PC3200 ram will do 2,2,2,5.. so find the cheapest if your going stock... If your going to push the fsb past 270, go TCCD, if your under that, try and get the new UTT sticks.
It's a matter of preference... personally I like my 2x256 PDP XBL that cost my 118.. currently doing 295x9 stable as a boulder. Like to think I'd match well against 2,2,2,5 at 270.
<b>"These are my thoughts, your mileage may vary."