Seems like a bug, it's been reported here:http://trac.openstreetmap.org/ticket/2514
Though nothing seems to have happened with that for months. I though it would be a fairly simple fix if streams and canals etc are named correctly.

I think it would help make things easier for the renderers (and other data users) if it was a separate tag (and it would be more backwards compatible).

Otherwise, how do you tell the difference between a drain that loops back on itself (so is a circular way), and a drain mapped as an area? You could use area=yes/area=no, but that's an additional tag to remember.
A different tag also means validators can warn of problems, as they do for non-closed areas for riverbanks etc.
Also, renderers could ignore riverbank areas etc, and just render the river as a line at lower zoom levels, or to make a simpler map.

In Scotland, it is legal to walk, cycle, ride a horse etc, just about anywhere (so long as you are responsible). See the Scottish Outdoor Access Code.

The wiki definition of highway=footway says "For designated footpaths, i.e. mainly/exclusively for pedestrians".
As there are not many paths in the countryside exclusively for pedestrians, I think its usually best to use highway=path. Plus add the appropriate access tags, ie foot=yes, bicycle=yes, horse=yes.
And its also a good idea to tag the surface=, and for mountain paths / hiking trails, you can also tag with sac_scale= and mtb:scale= etc.

For drains, is it worth mapping them as a way and an area, as is done with rivers (waterway=river/waterway=riverbank)?
eg waterway=drain (for a way) and waterway=drainbank (for the area). It means you can indicate the direction of flow.

The same thing applies to streams. Streams as areas are available from the OS Opendata vector maps, so it would be nice to map them in OSM.

@ Sanderd17: I presume the rendering of Johannesburg is different to London because it is not the capital. I think places tagged as place=city and capital=yes render at lower zoom levels.
As it is, Johannesburg renders the same as the surrounding cities. Maybe it would be useful to have a tag for big/important cities, that are not (national) capitals. Or tag it with the population, and render based on that.

The tag highway=incline_steep or highway=incline is intended to be used on nodes, not on the way (which should have the usual highway=path tag etc).
Though its not very useful on nodes, as it doesn't indicate the direction of the incline. So its now discouraged / deprecated.

Its better to tag the way with incline=up or incline=down, or incline=10% etc.

Also worth tagging the paths with the surface: osm.wiki/Key:surface
Its useful to know whether its the path is paved or gravel or dirt etc (though I'm not sure if any renderers use this).
And if its a hiking trail you can tag with SAC scale: osm.wiki/Key:sac_scale

Go to this webpage and pick the tiles you want: http://garmin.na1400.info/routable.php
The map tiles will be a bit bigger than just Crete, but it shouldn't take too long to download.

Might be more useful to use something like old_name:de to specify what language the historic name is in.

Mapsource lets you view the maps on your PC. You can do stuff like plot waypoints and routes, then send them to your Garmin. Or download the tracklog from your Garmin and view it on a map, plus you can split/join/edit tracks. Then save it as GPX format, and upload it to OSM if you want.

So I find it very useful for doing this sort of thing, using it with my eTrex. I'm not sure if your Nuvi supports uploading/downloading waypoints etc?

Also, you can select maps and send it the Garmin. So you could download OSM maps for the whole of the USA etc, then install into MapSource. Then you can just select some of those, and send them to your Garmin if you don't have much space on it.

Though note MapSource usually included with the GPS device, or with maps you buy from Garmin. Updated versions of MapSource are available to download for free from Garmin, but they won't install unless you have a previous version installed. Unless you use a bit of workaround, see the instructions here: http://www.mydigitallife.info/2008/01/31/download-garmin-mapsource-for-free-and-install-without-media/

As for the file sizes you mention, I think they are a bit mixed up. I suspect you mean 8MB, not GB. Though I think it would be easiest to just buy a 2GB or 4GB SD card, they are pretty cheap now. Then you can copy the OSM maps onto that, and not affect the preinstalled Garmin maps.

Assuming you are talking about this website: http://garmin.na1400.info/routable.php

It says on that page;
This service generates four different configurations of your personal map:
* Installer for Garmin MapSource (Windows).
* Installer for Garmin RoadTrip (Mac OSX)
* Combined image for direct manual placement on the GPS device (gmapsupp.img)
* A zip file just containing all the Garmin map tiles as selected on this website. This is useful for Linux users (e.g. Qlandkarte)

So these files are useful if you want to view the map on your PC, in different software.

Have you seen the table for international equivalence at the bottom of this page: osm.wiki/Key:highway
It specifies what type of roads should have what tags for each country.

Have you followed all of the import guidelines? osm.wiki/Import/Guidelines

Specifically, discussing it with the community, before you import anything. And documenting it on the wiki.
Also, how do you know that your "official" data is better than what was there previously?

I think there's a few problems with how Opencyclemap handles multipolygon relations for areas. It seems it applies the tags on the inner part to the whole polygon.
I think its the bug reported here: http://trac.openstreetmap.org/ticket/1656

Mapnik (the default map on the OSM main page) can take a while to update, and not all zoom levels are rendered at the same time.
If you wait a while longer (a day or two), it will probably all look correct. Its also possible you are looking at a cached copy, so worth trying Shift+Refresh in your browser.

You can also mark tiles as "Dirty", which will cause them to be rendered. More details here: osm.wiki/Slippy_Map

For those links in Keepright to work, you need to install the remote control plugin for JOSM, and have JOSM runnning when you click on the link.
osm.wiki/JOSM/Plugins/RemoteControl

What were you doing, and how did you end up with two copies?

Anyway, its easy to delete one of them:
Just open the relation list (Alt+R), select one of them, then click the little bin icon to delete.

It sounds like it is something about how you are using your Garmin. I can mark points in areas just fine on my eTrex Venture Cx.
Move the cursor to the point you want to mark, then press enter. It should give the option of Save / Map / Goto. Choose Save, and it will mark a waypoint there.

I would say if the path is immediately adjacent to the road, separated only by a kerb (eg a sidewalk / pavement), then adding the footway=both/left/right tag to the road is best.

But if the path is more separated from the road (eg with grass in between), then worth mapping it separately. As this means you can show where it actually is, and whether its parallel to the road etc, plus you can tag it with the surface / width / access.
Though if doing this make sure you map where it connects to the road, to help with routing.

The reference number itself may not be copyrighted, but the database may be. see http://en.wikipedia.org/wiki/Database_right and osm.wiki/Legal_FAQ
Yes, it fine to get a road number from a sign etc, but copying a substantial number from a database or other map etc would be questionable (and not allowed in OSM).