I'm a skinflint and not in the rarified heights of exploration so a custom duo simple (V2!) with an additional small "Chinese bicycle lamp" does me fine. Don't like the battery box though, just maybe I'll convert it to Li Ion but I like the idea of carrying several spares and being able to change
If I wanted bigger and badder and even more baderrer, personally I'd consider the 250lm for 16 hours you could get with Dragon EX (http://www.ledcaplamps.com/dragon_EX.htm) .
I'm sure Roy must be lurking on this thread but too modest to wade in? Come on Roy, set the record straight!
(Edit, corrected 12hr@250lm to 16hr@250lm.
Edit2 if wondering, my AV shows the Chinese bicycle lamp, but Duo removed and lent to other person who showed up lampless! Chinese lamp has a Petzl core that costs 6x more than the lamp, mastic'd inside it and runs 12-14hrs with wildly dispersed feet-to ceiling light, which I like in addition to relatively more focussed beam of duo)
Expert in incompetent tomfoolery