International Phone Service Shenanigans

The Road Show has been trying to figure out how to have inexpensive international phone service while traveling. We've been to France, Mexico, New Zealand and Australia in the last year and have yet to figure out what's best.
Here's a run-down of what I've tried:

The Set Up: I have an Iphone 4S. I have AT&T phone service.
Of course, every phone service has different plans and costs, so my experience is limited to AT&T.

I have two monthly add-on plans my phone: Each plan is about $5.00 a month

a: World Connect-allows me to call from the US to other countries for a cheaper per-minute rate.

b: International Roaming-allows me to call from a foreign country back to the US for a cheaper per-minute rate. This can be pretty cheap when calling to Mexico or Canada, but other countries can be $1.50 or more per minute.

Different things I've tried:
1. Global Messaging 50: this gives you 50 text messages per month for $10.00. You are supposed to be able to send picture and video along with text messages, but some foreign phone carriers don't allow the photo messages. You can add this feature and remove it after your monthly billing cycle to reduce costs.
Review: I used this once or twice and found it frustrating when the photos didn't go through. Messages received get deducted from your regular messaging plan.

2.  AT&T WIFI International App- This may be called AT&T Call International now.
Register and download the Iphone app. When connected at an AT&T sanctioned WiFi hotspot you can make phone calls for cheaper rates billed directly to your credit card. No monthly packages.
Review:
I tried this on a trip to NZ and never found an AT&T hot spot where I could connect and use this service.  The trick is to find an applicable AT&T sanctioned WIFI hotspot. It won't work from just any WIFI network.

3. Unlocked cell phone with local SIM card. I've used an older Nokia phone with a SIM card in France and Australia, and an Iphone 3S (IOS4) with a SIM card while visiting Sydney, Australia for several weeks. The SIM cards are easily purchased online ahead of your trip and easy to use.

Review: This is a good way to go if you are going to make phone calls within the foreign country-say to restaurants and hotels or to stay in touch with local friends. You can get data plans as well as calling plans for less money than I could get with AT&T. You can give your new phone number (that comes with the SIM card) to people at home and they can call you. You can also forward your home phone calls to this new number, but it could run up your charges. I have used the text messaging on this but photos don't always go through.

4. FACE TIME over WiFi: One thing that has been great is using the Iphone FaceTime feature. With my phone plan, I have to use this on WiFi, and it only works with other Iphone users also on WiFi. Users with set data plans can use Face Time over their cellular network. This is similar to Skype, but is easily accessed through my phone contact list.

I'm still undecided about how best to maintain phone service at a reasonable rate while traveling overseas. If you have any other suggestions, please share!

To keep costs down, I always do this with my Iphone:
 1. I turn off the cellular data usage feature (found under Settings>General>Usage) and stop all push notifications and automatic email loading.
2. Remember to put it on Airplane mode before I get on the plane. I can listen to music or audio books and videos already downloaded.
3. Upon arrival to the new country, I keep it on airplane mode and turn on the WiFi feature.