The most common conversion for those people working has to do with PDF, doc and xls. All Office Converter deal with them easily. It can convert doc into pdf, pdf into doc, doc into txt, txt in doc, xls in doc... as you can see you'll have no conversion problems anymore.
Furthermore it also supports text to image conversion, that means that you can create pictures containing text. Of course you can also convert between picture formats: jpg, gif, bmp...
It's very easy to use, you only have to choose the file or files you want to convert (it support batch file conversion) and then choose the output format in the list of formats in the lower part of the window.
15 days trial version