ISP broadband comparison in New Zealand @ $39.95

Say that we have an internet budget of $39.95 per month, which one is worth it?
(... I think Ihug.)

Xtra:
Data allowance per month: 1GB
Download speed per second: 256KB

Ihug:
Data allowance per month: 2GB + bonus 2GB (12am-8am)
Download speed per second: 2MB

Orcon:
Data allowance per month: 1GB
Download speed per second: 2MB

Woosh:
Data allowance per month: 1GB
Download speed per second: 256KB