With the coming in force of the new Trenitalia schedules effective December 13, 2009, the gap between the most expensive trains (the "AV") and the cheapest (and slowest) trains (the "regionale") has widened even more. Indeed, while fares for the AV trains have all increased slightly over 10%, fares for the slower trains (including the Intercity ("IC" trains) have remained the same as before.
The AV trains now provide even faster service: e.g. Florence to Naples in an INCREDIBLE 3 hours; Rome to Venice in 3 hrs., 48 mins.; Venice to Florence in 2 hrs.; Florence to Bologna in an INCREDIBLE 37 minutes!!!
But this speed comes at a considerable cost.
Travellers open to "trading" speed for a much lower fare should consider travelling on an IC train (with automatically reserved seats) or (where available), even on a "regionale" train (where seats can never be reserved).
Also, all trains EXCEPT the "regionale" have 7 and 15-day advance purchase fares which yield discounts of 15% and 30%, respectively. Unfortunately, it is virtually impossible to buy tickets on the Trenitalia website without a credit card issued by an Italian Bank (at least at present), making these promotional fares much less available to foreign tourists than was the "AMICA" fare for ES-City, IC, ICN and EXP trains which has now been DISCARDED. These promotional fares CANNOT be combined with other discounts.
Fares for the "regionale" trains, being already extremely cheap, are non-discountable.