jillian,
I would NOT recommend using a Power Bar, as the majority of models these days include some type of surge or noise filtering. Those models will likely self-destruct in spectacular fashion as soon as they're connected in Europe. There is one model you could use though.....
http://www.amazon.com/Monster-MP-OTG400-BK-Outlets/dp/B000F9YN2M
You most likely will NOT require a voltage "converter". What you MUST do to begin with is to check the Input Voltage specifications on EACH device you'll be travelling with. Most (if not all) of these will probably state "Input 100-240 VAC, 50~60 Hz", and if that's the case all you'll need is inexpensive Plug Adaptors specific to the countries you're visiting.
For travel in the U.K. and Ireland, this is the style that you'll need.....
https://www.magellans.com/itemdy00.aspx?ID=118,3681&T1=MEA33MCG
For travel on the continent, you'll need this style.....
http://www.amazon.com/Samsung-US-Euro-Plug-Adapter/dp/B004SRU37G
I'd suggest packing at least a couple of each, as they're small and easy to misplace. You should be able to find them at local stores in your area such as Best Buy, Wal Mart or at travel & luggage stores.