Entry level laptop: core i3 or amd a6?

I will most likely have to replace my 2 year old desktop Pc (300 eur) and am thinking of buying a laptop around 450 eur. Main use will be photo editing 12-20 Mp raw files. Don't think I will use photshop any more (I'm not sure CS2 would run on win7) and probably switch to Gimp.

At this price level, i've seen laptops built around i3 sandy bridge and amd a6, which one would you recommend. All of them have 15,6" or more screens, 4gb ram and 320gb hdd, which sound plenty for me.

Any other thing you'd look for (led panel?) or avoid (win 8?).

All comments appreciated. Thanks in advance.