Hey, i have telstra cable and VOIP as my only landline connection.

I just went through Slingshots iTalk which costs $9.95 per month and gives me free local calls and 500 mins free overseas calling.
Reliability is not quite up to your 'normal' phone, but its close enough. Like you, i hardly use the landline anyways.

I bought a Grandstream handytone 486 and you can plug ANY phone into this and it works with minimal configuration.

Saves me about $40 per month so i am happy enough.