So I'm going out on a limb and saying for an Australian outside Sydney and Melbourne now is certainly not the time to buy an iPhone.
Now picking up a second hand iPod Touch, that's another matter. I have a Touch, putting the 2.0 software on it has improved the base software, added the ability to connect to the 802.1x based wireless net at work and opened up Apple's App store. I expect within the next few days that I'll be able to unlock it and then all the neat applications developed outside the Apple wall will be available as well.
The list of applications available from Apple's store is growing fast. There are already a few I'm finding essential - an Evernote client and Zenbe lists just to mention two. All the useful applications seem to be pushing out updates at a fair pace as well.
So why not buy an iPhone? Well, it comes down to two things - the iPhone 3G only covering two of the three frequencies used on our 3G networks and the terrible state of competition in the Australian mobile phone market. If you live in the one of the big cities then you might be well served by Optus or Vodafone (who use one pair of frequencies, only one of which is used by the iPhone) while Telstra (may they rot in hell) who use both the iPhone frequencies have the worst range of plans with the worst data charges.
I'm expecting that as the iPhone's share of the 3G phone market climbs more people will want better plans at the same time as the stock shortages disappear then we will see some competition between the carriers and rates improve dramatically - particularly for people like me who make few phone calls and will mainly use an iPhone for SMS and web browsing. So don't buy now. January might be the time, wait and see what the Steve says at Macworld and make a buying decision then.
The second large reason is that the software Apple is shipping with the iPhone still has large holes. The quality of information syncing between your computer and th iPhone is still far from ideal. The Bluetooth functionality leaves a lot to be desired - it doesn't support stereo headsets, has poor support for sending, receiving and archiving SMS messages from the computer. I thought the lack of MMS was a shortcoming but after discussions with several teenagers feel they only need the ability to send and receive pictures via Bluetooth.
So wait and see what the next move from the carriers and Apple will be.