In my opinion it would be a Lenovo as a first choice, Asus second. I don't think I would even look at a Dell or HP at this point.
HP for example is not supporting any computer purchased before October 2011 with Windows 8. There is currently a sound driver issue with some HP lap tops with Windows 8 and HP is saying tough, they are not providing a driver to correct the problem. I myself have one of those lap tops and a friend at The Villages Computer Club also has the same problem. It will be the LAST HP product I will ever buy.
My own feeling is that Dell has not kept up with technology and that has caused some financial concerns with that company. Check out this link.
Microsoft May Back Dell Buyout - NYTimes.com
The guys that repair computers have the least problems with Lenovo's that any other brand.
VG