- Any time I want to convert anything online I usually run a Google search like "convert kilograms to pounds." I usually find an appropriate converter within a few clicks but have recently settled on OnlineConversions.com where all conversions are done instantly, on the same page. No click-through, no pop-ups, no searching, just easy conversions. [UPDATE August 2010: See comment for a helpful tip. Thanks Jared!]
- Translations are a little bit tougher. I remember using Diccionarios.com many years ago, since the translations are generally accurate and thorough. The price for high quality though was a limit on the number of translations you can do for free. This is one reason why I have gravitated towards Google Translate over the past year. It is one of those "good enough" solutions, not to be relied upon for high-quality or lengthy translations but just helpful enough to understand a quick word or general idea from any other language. It is a tool that is useful but imperfect, and provides utility above and beyond a standard dictionary in that it allows you to enter whole web-pages and documents all at once. You can see a terribly translated Spanish version of this website here, or a butchered French version here, for example. The overall point is that Google Translate can instantly give you a basic understanding of almost any website or document regardless of what language you speak or what language it is actually written in. I once needed to translate an entire English Powerpoint presentation to Spanish and uploaded the original Powerpoint document to Google Translate. I had to go over every word and correct many serious mistakes to make sure it was professional-level Spanish, but the Google translation made for a great starting point and made the process a lot quicker overall.