SERIAL vs. OIDs

Seeking informed opinion on what is better to use as a unique row id for
linking tables together in a normalized database, a SERIAL field or the
pgsql OID.  This is for an intranet application with a small user base,
but I'd like to make it robust and scalable where it is easy to do so.
My conclusions so far:

OIDs:

Pros:
    * They're already there; save a couple bytes per row
    * Specific method to retrieve after INSERT (maybe faster than SELECT
on the sequence)

Cons:
    * Not serial by table; hard to build linked table 'by hand'
    * not pure SQL

SERIAL:

Pros:
    * Based on fairly vanilla SQL
    * Easier to reproduce all or part of a db on a dump/restore

Cons:
    * Performance?
    * Extra id field redundant

I'm sure I'm missing something, and I'm not entirely sure how to weight
the points I've got.  Advice appreciated.

Please CC me.  I subscribed to the digest.

Jay