I can't see disabling Aero if it runs smoothly. It only requires a DX9 compatible video card and I can't think of anyone who doesn't have one of those these days unless they're a true luddite. The only DX9 cards I might consider disabling Aero for are the Geforce FX5200 cards because even though they technically meet the hardware spec for DX9, the engine and memory are clocked too slowly to deliver acceptable DX9 performance even those with 256mb. Any onboard video that uses shared memory I'd disable it for, too.

I've found 945G (that's GMA950) and its successors to work more than adequately for Aero. Same with the NV and ATI IGPs.