I've recently purchased a new laptop to take over my editing computer so I will share some of what I found out.
As mentioned the graphics card won't make Photoshop run fast, but what this means is that instead of the graphics getting it's ram from another source, it will be taking the ram from the computer. Eg if you have 1 gig ram with no graphic card, you might only really only have 944 meg of ram. That means that all the programs have to run from a lesser amount of ram than is written on the box.
another problem is that laptops that come with XP are becoming rare these days as everything is going to vista, but if you never go online with it it's a waste, why have better internet protection if it's not going on there?. So you have to do a bit of searching around to get xp these days, I found that smaller computer shops are better than larger retail.
The laptop I bought was an LG has core 2 duo 2.2ghz, 2 gig ram, 383meg graphics card. I'll put a link to it, it cost me 1700 after 200 cash back, come with XP but can run vista with ease if I have to upgrade.
http://au.lge.com/products/model/det...0s*a8x2a.jhtml
When I come to editing images however I find the old CRT's are better, to fix this problem I'm set it up with a dual screen, I have the image on the CRT and photoshop on the laptop screen. The best of both worlds.