What Laptop is really worth buying to replace a old Dell Laptop?

I have a Dell Latitude D610, and I brought it about three years ago.  It gives several problems such as, shutting down randomly, low disk ram, and low battery problem.  I need to replace with getting a new laptop. 

Now what since the Thanksgiving sale is approaching I will be buying a new laptop, but I need to know what kind of laptop is best worth buying,  A good one, with a nice amount of disk space, and a upgraded processor, and what brand is best?