removing precision from timestamp (microseconds) ..

From the docs, if you do:

traffic=# select CURRENT_TIMESTAMP(0);     timestamptz
------------------------2003-10-13 11:04:09-03
(1 row)

the 0 reduces the precision of the time to get rid of the microseconds ...
is there a way of having this done by default on, if anything, a per
connection basis?  For instance, I want to be get rid of the microseconds
from:

traffic=# select now();             now
-------------------------------2003-10-13 11:02:20.837124-03
(1 row)