One of the best choices, and definitely worth a close look. Great control center, small but helpful community, "just works" approach to software. I've installed it for 3 total computerphobes and have been almost disappointed by the lack of "support" calls once the initial settling in was over. PCLOS is maybe a couple weeks away from its new release with KDE4.4, which will require a rare reinstall, so if you can wait for that, all the better. There are also community versions with LXDE and other lightweight desktop alternatives if you want it even simpler.
It's not built on Debian, though. It uses RPMs with an apt/synaptic interface. The one possible disadvantage is that the repos have "only" around 12,000 apps available. Since the distro is designed as an integrated whole, installing outside packages is discouraged, which could be an advantage for the folks the OP describes -- everything they're remotely likely to want is there and they don't have to worry about incompatibilities, dependencies, and all the rest.