I always use Lenovo X-series.
Built like tanks, last forever.
I get them used -- 3-4 years old off e-bay, very inexpensive, hardly ever have any problems.
Even the x-200's (from about 2006) are running just great, but the newest X-1carbon (I have 1st and 3rd generation -- the new ones are up to Gen 6 or 7) are really nice.
Have to be a little careful about screen resolution -- one of them is very high res and AC isn't built for that, so works best if you scale down to 1366/768.
Dragon works on all of them -- 2 Gig is enough memory, 4 is probably better. One of my machines has 16 Gig and it doesn't make any difference.
The microphones on the X-1 Carbon are so good that I have given up using the special mics i used to have to use with Dragon, and I just talk to the screen.
