Postgresql Hardware - Recommendations

Hello,

My company has decided to migrate our Oracle database to postgresql8. We
will aquire a new server for this, and would very much appreciate your
advice.

NOTE: The applications accessing the database are developed and
maintained externally, and unfortunately, the developers have not yet
given us detailed information on their requirements. The only info I can
give so far is that the database size is about 60GB, and that it will be
frequently accessed by multiple users (about 100 will be connected
during business hours). The applications accessing the database are
mostly reporting tools.

I know that the performance question will ultimately boil down to "it
depends what you want to do with it", but at the moment I'm very much
interested if there are any general issues we should look out for.

The questions we are asking us now are:

1) Intel or AMD (or alternate Platform)
Are we better of with Xeons or Opterons? Should we consider the IBM
OpenPower platform?

2) CPUs vs cache
Would you rather have more CPUs or more cache? Eg: 4x Xeon 1MB vs 2x
Xeon 8MB

3) CPUs vs Memory
Would you rather have 4x CPUs and 8GB of memory, or 2x CPUs with 16GB of
memory?

Thanks in advance for all your replies!

Best Regards,
Christian Kastner