I've been following this thread with some interest. Here are some thoughts:

Need for a compass: Like hikermor and others, I find most of the time I don't really need a compass or GPS (although I always carry both). I spend most of my time in fairly rugged terrain, and just using my Mk I Eyeballs and associating terrain to map is all I need. However, as has been noted, in certain situations (relatively featureless terrain, poor visibility, etc) a compass is needed. I don't often need a compass, but when I need it, I need it bad!

Bubbles: Annoying, but unless they get rather large they aren't a big deal. It is usually fairly obvious when a bubble is big enough to interfere with the needle.

Compass in cold weather: Awhile back some of us were doing a navigation exercise in chilly weather. It was about +3 deg F (-16 C). Several people's compasses (all Suunto's as I recall) more or less stopped working! What seemed to be the cause is that the oil filling was getting so viscous that the needle could no longer move freely. My Brunton (Type 15) developed a bubble, but kept working. When they warmed back up the Suunto's started working again, and the bubble completely disappeared from my Brunton. Since in Alaska it does get cold now and then, a bubble is annoying, but a needle that doesn't move at all is unacceptable!

Awhile back I heard about the German made K&R compasses, which I believe someone else mentioned up thread. They might be the ticket for cold weather use. I recently ordered a K&R Alpin Sighting Compass. When I get it and get a chance to use it, I will post a report.

Accuracy with a handheld compass: Using a decent mirror sighting compass, you should be able to get withing 2 deg, plus or minus, if you are careful. This is adequate for most uses. I don't much care for lensatic compasses (though I confess I haven't a lot of experience with them). If you need better than 2 deg, I would go with a Brunton Pocket Transit. I've used them doing geologic fieldwork and they are an awesome instrument, but they are big, heavy, clunky, and cost $400-$600.

Declination and old maps: I would never rely on the declination posted on a map margin unless it was a really newly published map. Here around Anchorage Alaska, declination changes by about .34 deg/year. That means that the declination listed on a map published only 10 years ago would be off by 3 degrees or more. I always go to http://www.ngdc.noaa.gov/geomag-web/ to check current declination for an area.

Useful methods: I haven't found resection (or "triangulation") to be that useful for land navigation, though it is useful when boating. If I have several clearly identifiable landmarks around, I can usually figure out pretty closely where I am. However, I have sometimes found a variation on this method useful. If one is on a linear feature such as a ridge line, and has a single well identified landmark in view, one can plot an azimuth from the landmark to the linear feature and get a good fix. Deliberate offset (aka "angle off" or "aiming off") is also handy. The requirement here is that the objective be located along an easily identifiable linear feature.

Best type compass: For me, I find a good mirror sighting compass, with adjustable declination and a clinometer is the most useful. For getting a general direction I can use it like a baseplate compass. For more precise work I can use the sighting mirror. The clinometer is essential for getting accurate slope angles when traveling in avalanche terrain (those who don't go into avalanche country probably don't need it).