CURRENT_TIMESTAMP vs actual time

Hi,
I understand that CURRENT_TIMESTAMP marks the beginning of the current
transaction.  I want it to be the actual time.  How do I do this?
timeofday() returns a string, how do I convert that into a TIMESTAMP?

Is it possible to create a column with DEFAULT value evaluated to the actual
current time (i.e. not the CURRENT_TIMESTAMP which is the beginning of the
current transaction).

What I do now to get it to work is do a COMMIT right before the insert, that
way CURRENT_TIMESTAMP is (pretty close to) the actual time.  ...but that is
so crappy and doesn't work if I actually need to use transactional features
(i.e. rollback).

Thanks for the help,
-- C