Map 24 provide interactive street maps, complete with searching by address, points of interest and full directions, using an applet.
They presented a very good technical session on applets at last year's JavaOne, where I seem to remember that they said they are one of the most popular applet sites and are responsible for a lot for the JRE download traffic that Sun gets.
Try it out - the applet loads very quickly, is very fast at rendering maps and very responsive to use, so it's a great example to use to dispel the 'applets are slow' myth.
www.uk.map24.com