Exactly --- spare battery, works great. Solar charger can work well in areas that get a lot of sun, i.e., not hiking under trees all the time, and of course southern latitudes are better. There are also little separate units that take a AA lithium battery and deliver charge, but my personal experience with one of those was poor and I've read mixed reviews; they seem to work pretty well for some people/phones. I've never heard of anyone using hand-cranked units for any real significant power boost.

Apps to consider; I recently posted something about this on a similar Whiteblaze thread, so I'll copy/paste that here:

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One app you might consider (search the app market) is Droidlight --- turns your phone into a battery-burning flashlight. Obviously something you hope to never use, but maybe as a backup light source, i.e. use to change batteries on your primary for example.

Some sort of book reading software, such as Aldiko. I don't read on the trail much, but can be nice when waiting for your laundry in town or that sort of thing.
I suggest that you look round to find some sort of backcountry first aid book(s) for it.

Consider which browser you like best; maybe not the default one. I'm using Opera Mini now, not sure which is best.

Some sort of software that allows you to journal, if you're inclined (I bring a folding blutooth keyboard for mine). Quickoffice is free, consider installing that.

I like having a voice recorder, so consider something like VirtualRecorder.

I don't like the default calculator, so consider finding a replacement (I prefer RPN calculators and so found one of those).

I suggest that you get the "advanced settings" app so you can turn off the phone "radio" without explicitly going into "airplane mode".

Certainly some good mapping software would be good, I thus far have no experience at this (other than google maps) with this phone.

I suggest that you look at gear manuals for any gear items you carry that are at all complicated (for example, maybe an altitude watch) and find those in pdf form online and put them on your phone. I rather like having gear manuals for several items along with me in electronic form.

I would encourage you to play with the phone quite a bit before starting, try to do all the things you plan to do on-trail while doing day trips or, better yet, some local backpacking. Figure out which icons you need readily available, learn how to use the camera well enough before you lose photos due to lack of familiarity. Above all figure out how to minimize power drain; a particular issue I have with this phone is a relatively slow boot time, thus I'm more inclined to try to keep it "on" with screen turned off, and work hard to eliminate background power-sucking tasks.

I figure I'll really be getting to know my new Droid X by the time I've finished my next long trip ...