Centrino wireless suppor tis supposed ot be unique. I think that the ONLY advantage to Centrino is battery length is longer.
My laptop has built in wireless networking with the antennae in the screen, which has a titanium reinforced grid behind the display.
PIII M 1.13Ghz, 640 MB RAM, built-in wireless.
It runs like a top. I haven't found someone with a newer Centrino or AMD that outperforms it yet.
Even P4M's seem slower.
As Chas said, Manufacturer is very important. My Thinkpad was a little pricey, but the 3-year onsite warranty has replaced my DVD(when I dropped the notebook and bent the tray) and the Keyboard (I picked up my cat from my keyboard and he pulled two keys off). No cost, with a happy "Is there anything else we can help you with?"
Compaq offers good support (I prefer their Desktops) but I'm not big on the notebooks, even though the EVO series is pretty nice.