Few modern devices require voltage converters (i.e., transformers). Anything portable and electronic is almost certainly voltage- and frequency-agnostic.

The most common travel-related devices that care what voltage you connect them to are those with heating elements or motors: irons, hair dryers and curling irons. If you have a single-voltage version of one of those, you're far better off buying a dual-voltage one before your trip or buying a cheap 240 volt one in Europe.

Once you've avoided the voltage issue, all you need is a couple of good-quality adapters.