Should I bring my cell phone. Or buy a SIM card in Europe?

"and buy a cheapo cell phone for use only in Europe. What do you suggest?" Your choices are explained here: http://www.ricksteves.com/plan/tips/mobilephones.htm

I took my iPhone with me for 37 days. Kept it on airplane mode with WiFi re-enabled. Had WiFi at most hotels. I purchased the 50 MB International Data package to use when WiFi wasn't around (to use, I would turn Airplane mode off). It cost about $60 for a month I believe. I used Skype on the iPhone when in WiFi to make calls (I believe it would work on 3G but would use up massive data). I only made one "local" call on my phone the entire trip (which probably cost me $4). I used the hotel phone instead once to book a tour which cost $0.50); otherwise I had the hotels make calls for me. Skype worked great for making long-distance calls, but not perfectly (you have to watch your signal). I paid for $10 of Skype credit and still have $8 leftover.

Thanks Kent!

The only addition to the RS advice is that in the UK you can buy unlocked Pay As You Go mobile phones for a lot less than 60 dollars. They can cost as little as £15 including £10 of call time. Also in the UK, If you already have an unlocked phone you can get SIMs where all you pay for is the actual call time on them.

Just to be clear, the $60 was for data. I spent only $6 on phone calls.

Marshall - I was talking about the RS advice that unlocked phones cost about 60 dollars in Europe. Just a coincidence that your figures were the same!

Ahh - well, it's all perfectly clear now. :)

Our iphone experience is similar to Marshall's. We used it just the same way while in France. We kept data roaming turned off unless we needed the internet while away from wifi. Data use was reduced by turning email push off for the whole trip and only checking email on wifi. We didn't download any maps and watched the data use closely. We spent less than $130 for 34 days. We had a French mobile, but used the iphone's phone function several times anyway when we needed a second phone. The iPhone is a very handy device to have while in Europe. ATT's international phone and data roaming plans can keep the cost reasonable if the use is monitored. But if you'll need to use the phone a lot, you should get a local sim.