I would suggest that the installation of extraneous kernel-devel packages (i586 when you already have i686.PAE to match kernels) is potentially problematic: compilers (like those used by the nvidia drivers to build kmods) looking for kernel sources could become "confused" and use the wrong sources. It is possible that in some cases, you might need both, but unless specially/specifically required, I'd avoid such "mixing" of kernel-devel packages. I consider the compilers to be "stupid" enough to make such mistakes.
Perhaps now would be a good time to get a definitive answer on the above from someone more knowledgeable (Leigh ?).