After seeing a talk about kayaking, I'm inspired to try and go kayaking more. Haven't been in ages. But apart from that, I'm also inspired to make sure we have "the Grand Canyon of the Stikine" on the map, and also on on kayakwiki.
It's a big wide wilderness out there in that part of Canada. The SRTM data presented as releif maps (by the cycle map), makes it fairly obvious where the big rivers are. But it took a bit of detective work to figure out which one the river Stikine was. I guess it would be fairly doable to take SRTM data and draw in all big rivers in an automated way. Could be good for remote wilderness areas where nobody's going to get around to adding in even the big rivers any time soon.
In this case I sketched the river's path in from yahoo (satellite) imagery. This is more precise than SRTM, but less machine automatable.
In this case also we have a Canada import pending, which means it's not worth going to any effort to do anything clever with SRTM. The Canadian government has some good map detail. Lots of little rivers, all with names, and other things like mountain names. See it (through a fairly pants interface) here.
But in other wildernesses of the world like Alaska or Siberia, maybe it would be worth experimenting. It'd be fairly imprecise based on SRTM, but precision is relative thing. If you're slapping in a massive river, it can still look accurate enough at zoom level 10 and below. Better than not having the massive river on there (in wilderness areas where we're unlikely to map them via other means any time soon)