Comparing lithuim ion and traditional NiMH then yes NiMH self discharges faster but the newer low self discharge NiMh are about even with lithium ion.

The problem with your example solution is your listing one top of the line charger for one device. You can use that same Maha c9000 for a dozen different gadgets so the price gets divided between all of them as well as the pack weight. With lithium ion devices you need a charger per unless in the race case of a flashlight you can charge individual cells.

So look for example:

AA Solution
$50 Maha C9000
$50 AA Powered flashlight
$200 handleld GPS
$200 two way radio
$200 digital camera
$50 couple dozen Sanyo eneloops for each and spares for each

Lithium Ion solution
$15 lithium ion cell charger
$50 lithium ion powered light
$20 LG 18650 3.7V 2600MAH
$200 handheld GPS
$20 Power supply/charger for GPS
$30 Spare battery pack for GPS
$200 two way radio
$20 power supply/charger for radio
$30 Spare battery pack for radio
$200 digital camera
$20 power supply/charger for camera
$30 Spare battery pack for camera

remember the maha comes with a wall and car charger so to get the equivalent with the lithium ion solution each device usually comes with a wall charger but then you need the vehicle charger or an inverter. The bateries are all different, the one from the gps won't fit the camera, the one from the camera won't fit the gps, the one from the gps won't fit the radio, etc.
Even if you eliminate the second chargers you still have 4 instead of 1. Ok sure its nice you can charge everything at once but you can buy 8 bay nimh chargers or buy a pair of c401fs, etc.
You still can't share the lithium ion batteries between devices.
Again, your solution does look best if you only look at flashlights, as I said before, but looking at a bigger real world picture, newer technology (low self discharge nimh), ability to share the spares, and the ability to supplement with a $10 bulk pack of 30 AA's if needed the advantages of lithium ion are quickly outweighed by standard AA's