Oh no not this again.
Yes, the laptop GPUs would be fine. Performance would be great. We're talking desktop framebuffers here people, not gaming. In 1996, GPUs could push out desktops at 1600x1200 without sweating. I think 15 years later, we're covered for way more pixels.
As for gaming, just drop back to a lower res for 3D graphics.
Actually, we're really not talking about desktop framebuffers since everything on an OSX desktop is an OpenGL backed rendering context, so the comparison to 1996 1600x1200 doesn't apply. The issue becomes having textured geometry and effects that are now rendering 4x the pixels through the GPU pipeline. Even back in GMA 950 days of the MacBook I would argue that the desktop wasn't really performing that great..
The new Intel 3000 IGP is really great though and with the 4000 of Ivy Bridge I am sure it will be great, but I think the real key is that the GPUs are really getting incredibly capable