Though the price for the Galaxy Nexus keeps on going down ($400 currently), $665 seems like a reasonable price for 1 years worth of unlimited calls and text and 5GB data per month.
Similar to this deal: http://www.ozbargain.com.au/node/71348
Essentially the phone will cost you $300 and the prepaid recharge of $365.
Unfortunately it uses the Vodafone network, which may not be great for some, though this phone should be able to use the 850 network.
There are cheaper overall alternatives such as purchasing outright and Liveconnected $11/pm Tribe plans, however for unlimited calls and text, it seems rather reasonable. Note that data is charged in 250kb increments unfortunately.
Edit: It's 250kB increments.
http://www.ozbargain.com.au/node/74571
They have the Galaxy Y for $100 ($465 all up) which is very cheap.
I see the Galaxy Nexus is due for JellyBean very soon.