The claim about Voyager1 being the fastest spacecraft at 38,500 mph is no longer correct - New Horizons is now at about 47,000 mph following its recent Jupiter flyby, and this AerospaceWeb article claims that the record really belongs to -

two vehicles called Helios launched to study the Sun during the 1970s. Both of these probes attained maximum speeds of around 150,000 mph (250,000 km/h) at closest approach to the Sun in their highly elliptical orbits. Helios 2 was slightly faster than its twin craft, and this probe still holds the speed record as not only the fastest spacecraft but also the fastest manmade object in history.

As they also point out, even if the record is restricted to long-distance probes, then NH comes out ahead following the Jupiter gravity-assist (or more accurately, angular momentum transfer)

Nice page though - lovely pic, and a sweet thought of our sun seen from afar.