No gaming graphics cards if you wanna go for 3D modeling. Go for Quadro of FireGL cards. They are totally optimized for modeling and suits your needs perfectly.
If you are totally serious about 3D and Maya, Go for Core i7/Quadro rig. I wouldn't recommend Phenom II or Geforce or Radeon here for you.
In case of laptops, these are pretty hard to find in USA and impossible to find here in India.
+1
^many reasons for its acceptance, the primary being Quadro card have support for hardware rendering. this feature is not available in ANY other series
personal experience:
i own a 120AMP.
2.6 C2D
3 GB ram
as you know very good graphic card. supreme gamming experience.
had to do some rendering for a professional friend, one scene in 3ds max took 35 mins HIGHLY unacceptable.
he got
a Quadro FX 5600 and some CUDA APIs (I dont know the stuff , only provider for HW must be highly professional) ---took ONLY 7 mins
go for a professional config.
only a high-end graphic solution will not help you in any way