If you're not plausibly going to be storing more than 1GB of binary data in a single field, you might as well use the normal bytea type instead of LOBbing it.

They won't bloat the table as PostgreSQL would store the larger byte streams outside the table anyway (as Large Object storage does, only transparently) - including compressing them if it helps - while retaining all the binary string functions and operators.

IMHO, there's a better way to handle the deletion of lob objects than the suggested here. The programmer can easily forget to unlink the lob. With the following trigger, no programmer actions are required.
By the way, one problem with bytea fields is that when you query the database, if you ask for that field, the data is actually retrieved. When you query for and oid, only the oid is retrieved and then you can open the lob whenever you want (if it's required).

CREATE OR REPLACE FUNCTION oidtable_after_update_delete()
  RETURNS "trigger" AS
$BODY$
BEGIN
     IF (TG_OP = 'UPDATE') THEN
        IF (OLD.oidfield = NEW.oidfield) OR (OLD.oidfield IS NULL) THEN
           RETURN NEW;
        END IF;
     END IF;
     IF (EXISTS (SELECT 1 FROM pg_largeobject WHERE loid = OLD.oidfield)) THEN
        PERFORM LO_UNLINK (OLD.oidfield);
     END IF;
     RETURN NEW;
END;
$BODY$
  LANGUAGE 'plpgsql' VOLATILE;

CREATE TRIGGER oidtable_after_update_delete
  AFTER UPDATE OR DELETE
  ON oidtable
  FOR EACH ROW
  EXECUTE PROCEDURE oidtable_after_update_delete();