Basic choices:
1. Arc AAA, Peak Matterhorn: high quality 5mm lights, no nonsense, long runtime, moderate brightness.
2. Fenix E0, River Rock, etc.: similar to above but lower cost and lower quality
3. Fenix L0D CE: computerized, multiple brightnesses including a high level tremendously bright for such a tiny light. Runtime is somewhat unpredictable because of the varying current drains depending on brightness level. Build quaity decent, not great. Basically this is a miniaturized version of the 1x123 lights of a year or so ago, made possible by the Cree led. Fantastic little light but by your description, maybe not really what you're looking for.