Data is very useful for maps, web searches, etc.
Options:
1: Your own carrier international plan
2: A country SIM Card (voice and data)
3: OneSIM Card - usable in many different countries, data can be very expensive. I learned that the hard way in Turkey which didn't have a special plan. Be sure to set up auto-recharge at about $25 each time it falls below $10 or so.
http://www.onesimcard.com/faq/
4: Skyroam
$10/day for data, gives you 24 hours of data. You activate 24 hours whenever you need it. They usually give discounts if you buy multiple "days" or refer friends
My recommendation:
Look into your current wireless options to see if it makes sense. If not, get the OneSimCard AND Skyroam, then decide on whether or not to get a country SIM card for data and phone. Most of our international trips were roughly 12-hour time difference from Berkeley, so we used Hotel Wifi in morning and night, and cranked up Skyroam every 2-3 days, usually when traveling between destinations.
Whenever we'd get a new guide, or check into a new hotel, I'd have them use my cell phone to call themselves; that way they knew who I was, and I knew how to reach them.
Here's what we found over recent trips. If less than 1 week, I didn't bother with local SIM card
Turkey - OneSimCard data got very expensive, they didn't have a data plan at the time
Morocco - Bought Moroccan SIM card for phone and data. Worked GREAT!
Japan - OneSim & SkyRoam
Berlin & Bulgaria - OneSim & SkyRoam
Cancun - OneSim & SkyRoam
Cuba - OneSim worked only for phone calls, neither that nor Skyroam worked for data. We bought 1 Peso 1 Hour data access scratch cards and used at major hotels
Ira Serkes