There is just SOO much to choose from. It all depends if you want it simple or sophisticated (or both!), cheap or not so cheap. You have had lots of good suggestions already.

I suggest you get a light that has more than one level (mode) of output. The least bright mode will still be plenty for most task and with looooooooong runtime. The brighter modes will serve you well for looking further ahead and illuminating a larger area. You typically just need to use the brighter modes in shorts bursts. Multimode lights used this way enables you to preserve batteries and still illuminate things ahead when you need to.


If you want high quality and performance, I suggest fenix, quark or nightcore. A very good dealer for these lights is http://4sevens.com/. If that's too expensive ($50-80 range) I suggest ordering something from http://www.shiningbeam.com. If you want to combine the words "cheap" and "reliable" he is one of the few dealers that can be recommended ... Guess around $15-40 for something useful in the AA format from him. The cheapest possible will be a single level light, raise the bar until you're happy... The maratach suggested above is also supposed to be a very good light. I'm not sure if that fits into the "cheap but reliable" or "upper class, but still won't break your bank" class....


Oh, and probably the toughest lights of all would be the $12-15 fenix E01 (AAA format). Not the brightest, but it is a very small, sturdy light that is next to impossible to kill. Its simplicity (twist on) makes it extremely reliable. Long runtime (10 hours + 11 hours declining "moon mode"), still bright enough for most close range work. Use either an low self discharge AAA (LSD, such as sanyo eneloop) for regular use or possibly a lithium AAA if you want to store it indefinetively and forget about it until needed. Want more levels? Maratach, fenix LD01, ITP...