For everyday need even a dual-core atom with an HD chipset would be enough.
Sadly companies do mostly not offer such things.
While ITX platform is very expensive, they are selling like hot cakes. The J&W minix board had exceptional success in Asia and Zotac is selling dual-core Ion boards also with much success.
Gamers do need more powerfull machines, but not because the CPUs are so slow, but the games are programmed with C++ or C# which does take away much performance. Even high-end graphics-card can't compensate for bad programming