I can tell you it runs great on Debian, both stable or unstable. Stay away from testing since it lags security updates. Many OpenACS developers use Debian.
I believe there would be no problems to running it on recent RPM-based distributions. There's also Gentoo, which several OACS'ers use.
If you need Oracle, then your choices are limited mostly to the distributions supported by Oracle, if you want to stay on the safe path. I have heard of quite a few people with Oracle installations on Debian though.
-Roberto
