Looking for something a little unique (and best of all, CHEAP?). Well, Elgorithms have released a cool standalone tool for converting raster graphics into vector (DXF) formats openable in Adobe Illustrator. This ability is by no means unique, of course, but their tool,
MagicTracer is different in that it provides the ability to edit the original raster and traced image simultaneously (essentially by means of a neat overlay feature).
MagicTracer can be purchased for $49.95 USD on the MagicTracer site. A trial version is also available for download.