For lights not used often, I would go with primaries. Especially if they're in a car or otherwise exposed to temperature extremes.
Rechargeable lithium ions really shouldn't be stored at anything other than about 50% or so (some say even lower). So do you want a seldom used light with half dead batteries waiting for you when you need it?
In the NIMH world, we have Eneloop rechargables. If you can use those (AAA or AA sizes) for that form factor, do it. They're designed to be ready to go, fully charged (or darn close to it) over long periods of time.
Lithium rechargeables are best for frequently used lights. Even if you care for them and store them at the optimal voltages, levels, etc., they have a 2 or 3 year life span so the clock is ticking, using them or not (however, I hear the newer ones live longer).