Molto grazie Effendi! I suspected there was a reason that you didn't list that plan.
As we will be spending time travelling between cities and exploring Tuscany I think that I will stick with TIM because they seem to have the best 3G coverage. I'll try the TIM Internet 40 and be careful not to waste too many 15 minute blocks just checking email or using Google maps. I will also be careful to draft blog posts on my computer before connecting to the Internet!
Finally, I think I noticed a mistake on the Prepaid Data in Italy
web page. Under "Time billed offers" the TIM Internet 40 and Internet 100 are listed as having the same cost and time limit (€ 9.00/month for 40 hours). The Prepaid Data in Italy
forum posting appears to be correct.
Thanks again!