I still like the Garmin units. I use a 60Cx on the Ninjette; on the BMW I use both a Zumo 550 and the BMW Navigator IV, which is a branded version of the Zumo 660. Their current motorcycle specific units are the 390LM (a little less than $600), and the 590LM (a little less than $800). Both are quite pricey. They do come with motorcycle mounts, motorcycle power cables, have large glove-friendly screens, and have free lifetime map updates, and can speak to you through your bluetooth headset. If you're just using it for mounting on the bike, you can't go wrong with either.
If you're planning on using it for hiking, on the bike, and in cars, you might look into something like the GPSMAP 64. It goes for less than $300, but you then need to add City Navigator NT for $80 for the full US mapset. The device has enough memory that you can put it all right on the built-in memory, but it also supports microSD cards if you need even more memory (and want to load all street maps, plus hiking/topo maps). You would need to add a Ram Mount (
like this), and a 12V power cable (
like this). All in, it's probably $450, but that's still cheaper than either of the motorcycle specific ones, and it's more capable for one that's used for a variety of different use cases.
You can also go much cheaper with the Nuvi line, but make sure that you can add routes to it, some of the lower line ones are surprisingly limited. I don't know much about the differences between the Montana, Monterra, Oregon, or some of their other product lines; but none of them seem to be better than what's already listed for motorcycling use.