You're right, even though the voltage in on-base housing has both 220 and 110 available, the 110 is 50 Hz instead of the 60 Hz we have in the States. For the most part you won't notice any difference. We had to buy a pair of 220v hair trimmers because the 110v ones makes a TON of noise at 50Hz. I have heard that running US stuff at 50Hz will wear it out faster because it's simply not what it's made for, but I don't know if that's true or not. All of our 110v appliances (in the kitchen/bath/office/bath/bedroom) seem to work fine.
Something similar to keep in mind though, the power here is much less reliable than in the States. We loose power regularly for no apparent reason (just kicks off and on after about 3-5 seconds sometimes 5-6 times a day) and we have power surges much moreoften than in the States. So if you have any sensitive electronic gear, you may want to invest in a good surge protectors.
Also, you have probably heard not to bother bringing any electric clocks (neither digital nor analog) because they won't keep time because of the 50Hz (use battery powered ones or just buy a clock here, but since th epower goes out all the time batteries are better anyway), and you have to use Italian light bulbs here.
A dehumidifier is a really good thing to have here, whether in base housing or out in town.