The official SVG logo sucks and should not be used IMO.
Justinas brought up the example of PDF, which is a good example. For years, PDF was the format of Adobe exclusively. Other tools developed later on, but that format is still known as "Adobe PDF", and Adobe, to this day, holds the patents for PDF. The Adobe PDF logo is the official logo for PDF: http://www.adobe.com/misc/linking.html
I don't think Inkscape logo can be used as-is, but perhaps as part of a separate SVG logo. My advice would be to create the logo from a stylized form of the letters SGV as this is the only think I can think off that actually communicates SVG and then add the Inkscape logo:
(Of course, make it nicer, it's just an quick knock together.)