If you are using the system for the basic computing tasks that you list, don't worry about it. Just buy the fastest, cheapest thing you can find.
Having said that, the second generation Wolfdale cores are, clock for clock, a little faster than the 65 nm Conroes.
I have a Wolfdale based 2.93 GHz E6500 in a G'byte G41 motherboard doing basic computing tasks. It hardly ever drops out of SpeedStep.