I am a grad with good honours from a local university.
Where I am working now, I am starting to feel its better not to spend that one year pursuing honours unless you intend to work in civil service. Its better to spend that one year starting work early and gaining more experience / earning power.
I have one colleague, we joined the company at the same time. He did not do honours (just a 3 year course) and by the pay structure of the company (all starting pay is the same), now he is drawing the same pay as me. And I'm no slouch at work either (Not the lam nua kind). What the heck!

It might be a better path to skip the honours year and go out to work and gain experience and one day do a Masters course. But of course, some Masters courses require you to do honours (but not all).
Conclusions - one should not do Honours if:
1) One does not intend to work in civil service.
2) One intends to work in civil service but does not let the $$$ difference get to you (honours grads earn more)
3) Honours is not a pre-requisite to getting into your industry of choice.
4) You intend to work in sales / marketing / trading.
5) You intend to work overseas, in some country where companies not give a damn whether you have honours or not, or 1st or 2nd class for that matter.