Dual monitor setups are very nice indeed for heavy PhotoShop usage.
Regarding video card, your Radeon LE is actually very suitable for PhotoShop.
I'd probably pass on nVidia as 2D visual quality tends to be somewhat lacking on many nVidia boards, though if your running in relatively low resolution this may not come into play.
Unless yor running dual monitors and doing some real heavy PhotoShop editing, then 2D performance also won't really be a factor as most any modern card is more then adequate for almost any 2D performance related tasks.
Personally, I'd tend to look for a Matrox G450/G550 for their top notch 2D, and multi monitor implementation.
As a secondary option, a Radeon 7500 would do very nicely.
If your looking to save money though, the Radeon VE is a very solid card for multi-monitor PhotoShop usage and available quite cheaply.