Gatsby
Enlightened
I'd lean toward the LF2XT if you're set on AA or AAA. The versatility of the UI will allow you to set it however you want, from a very low low and days of runtime to a very usable high. If you want two modes I typically like the Fenix L1T v2.0 but the Quark AA tactical really is an upgraded version which allows you to choose the settings for bezel tight/loose among 8 settings (5 brightness and 3 signal) so I'd go with that one.
If you open it up to CR123 I'd lean toward the Novatac 120P or the Liteflux LF3XT.
If you open it up to CR123 I'd lean toward the Novatac 120P or the Liteflux LF3XT.