If you're starting fresh:
PostgreSQL 7.1.2, --with-tcl if you want to use the search for bboards.
AOLserver 3.3ad13 - fixes a memory leak and other things.
OpenACS 3.2.5.
The RPMs (and Debian packages) put things according to the Linux Standards Base. I personally like it much much much more than the popular "/web" and "/usr/local/pgsql". For one, libraries should go in in /usr/lib. When I install PG from source, I have to include "/usr/local/pgsql/lib" in my library path. If I install it from the Debian (or RPM) packages, I don't have to do anything because the libraries are put in the correct locations.
I haven't used the RPMs but I heard very good things about it. They work and Jonathan has done great effort to keep them nice and clean, a work for which the community is grateful for. It makes setting up a machine much faster.
But there's nothing wrong with doing everything from source. It's up to you. But it's better to choose either one, by that I mean either install everything from RPM or everything from source.
