I just use a plug adapter since almost everything made in the last 10 years can use any voltage from 100 V (Japan) to 240 V. To make it easier, I have a good power strip that takes up to 240 V and plug the adapter to that end, then plug all my stuff into the strip. I only need one adapter for all the countries I visit for the power strip, and have enough outlets for everything (2 phones, tablet, GPS, camera charger, shaver). Since many USA hotels also don't have a lot of accessible power outlets, I take the power strip with me all the time.
The shaver plug in a hotel bathroom is often 120 V, but is sometimes current-limited, so one can't put many devices to charge there. It also doesn't have the ground prong.
Also, if taking a computer, take an HDMI cable. The flat screen TVs also make great second computer monitors for laptop computers.