Routeslip - cool site, but slow, and inconsistent...good luck trying to plan a long route...
BikeRouteToaster - the only one with auto-routing, when it works, pretty cool, won't store the route for you...
Gmap-pedometer - sort of a predessor of the rest...
Bikely - getting better all the time, was once not quite as cool as Routeslip, but now it does everything and is faster...
GoogleEarth...your best bet for longer routes, but that's only because it's not web based, won't offer some more bike related options that the others might. I usually use GoogleEarth to draw the route then convert the KML to GPX and import it into one of the others...

There's this Linux forum that I head to for questions everyonce in a while, they've got a FAQ/How-to section that contains the most commonly answered questions that would otherwise continue to show up endlessly on the forums themselves. You can see where I'm going with this...