I believe that the best 13" laptop you can have today is a Macbook Pro, and not because it's made by Apple, but rather how it's put together. I've yet to come across a PC in its price range that would have outdone it in CPU power, Graphics performance, battery life, display image quality, and portability all at the same.
It's what I consider to be the most balanced piece of electronics you can have today, and it can be had with an SSD for some extra. I'd recommend you choose a 2.5" SATA SSD and install it on your own, as you're allowed to without losing warranty.
If you're still keeping distance from these laptops, take a look at Lenovo models at around $600 to $800 for similar processor performance, without the luxury of the dedicated video chip. Some people don't care about it as they don't play games, but I don't have a desktop PC so everything I do is done on my Mac.
If you'd asked a few months back, I probably would have pointed you towards Sony Vaios, but having had the pleasure to disassemble one (broken display), I can tell you that they're nothing extraordinary in terms of build quality and the durability of components used when compared to Fujitsu-Siemens, for instance. Fu-Si, is one brand I do not recommend based on the same aspect; once you take them apart, and sooner or later you'll have to, you'll wish you'd never given money for it.
I know I haven't mentioned that many exact model numbers on the PC line, but that's only because I don't know what is it that you think is the most important in a laptop. I'd stay away from the masses of integrated VGA laptops (Intel GMA, in particular), and check weight before you do anything. Trust me, you probably don't care now, but going for one that weighs over 3 kilos (6.5 lbs or so), you'll hate it more with every day.
About 15.4" laptops, the Macbook Pro of that size costs about 50% more than the 13" model, but it offers that much raw cpu and gpu power with only a little shorter battery life.
My 13 goes on for around 7 to 10 hours when I browse wirelessly and don't use flash, and around 4 to 6 hours when I do. Playing WoW is the heaviest use it gets, which puts the battery life to 2.5 hrs. You lose 20% of those figures by going 15", but you gain about 50% of sheer performance on all fronts.
Hope it helps.