Re: Is every laptop with optimus unusable?
It's not fully correct. There are laptops (ASUS UL30Jt for example) where you can disable intel's integrated card from BIOS.
With ACPI Call or by modifying of DSDT you can disable nvidia's card when intel's one enabled. So you can switch (in BIOS) between Intel and nVidia.
But anyway, optimus itself doesn't work on Linux.
OS: Gentoo Linux, ~amd64. VideoCard: GeForce GTX 470. ASUS P8P67 Deluxe, 2x4GB DDR3-1600 CL9, Core i7 2600k.