Currently the only computers that can be used without the ME are those supported by LibreBoot, but they are old and consume so much power.
You forgot about AMD ! The latest AMD-without-PSP is significantly more powerful than the latest Intel-without-ME - and there are AMD platforms supported by the opensource coreboot BIOS. Actually, we have been discussing one of them - Lenovo G505S - here: Lenovo G505s - #5 by mike_banon . Quad-core CPU, 16GB RAM, no PSP, works fine with Qubes (i.e. because IOMMU is functional with coreboot), and thanks to coreboot you can be sure there are no backdoors in BIOS