That's my experience too, but be warned that the latest ATI chipset (Evergreen a.k.a. R5xxx) is still not fully usable with the open-source driver; no clock-throttling (bad for battery life) and no DRI support yet, despite the hardware being released last autumn.
My netbook (Intel graphics) can perform 3D effects that puts my laptop (ATi) to shame, and the power drain from the GPU means I barely get 90 minutes of usage out of the standard battery.