how much difference does dual channel make?

[freebooter]

Currently have one 512 stick of generic ram in my shuttle and thinking of upgrading to 1Gb. The chipset is an nforce2 so it will run in dual channel mode. Trying to decide whether to just buy another 512 generic and run in one channel or to buy a dual kit and sell my generic.

Main use is general office work and image editing. Hardly play games at all now although Oblivion may tempt me.

Is it worth going dual channel - how much difference wil I see over 1Gb in single channel mode?

thanks