Very pricey (Amazon beats Wal-Mart hands-down), but they last the longest of any battery source. Consumer's just reviewed batteries for power-hungry digital cameras and confirmed same. I use 'em in my battery-eating HeadRoom Super Bithead portable headphone amp (4-AAA) along with my iPod Classic and Shure SE-530PTT music rig, and they outlast multiple sets of Duracell copper-top and Energizer Max alkalines. I carry an extra set in my computer bag so i'm never without my tunes! LOL!

Oops. I didn't realize there are TWO different types of lithium batteries: plain and rechargeable. I bought these, which are the plain type, but I meant to buy rechargeable. Though they're not what I wanted, for non-rechargeables they're pretty good.

These new Lithium batteries does provide much longer power strength and intensity than regular alkaline batteries. However, effective January 1, 2008, the Department of Transportation prohibits loose lithium batteries in checked baggage. This type of primary AA / AAA sized Lithium battery is within the ban.

Basically, if by any reason this type of battery caught on fire (AKA lithium fire), few regular fire extinguisher would work to put off the fire! So make sure those batteries are packed into the electronics and put them into the carry-on luggages with you!

SEE http://www.tsa.gov/travelers/airtravel/assistant/batteries.shtm

I've gone through a couple packs of these in my GPS unit. They don't hold nearly as long as it seems they should considering the higher price compared to alkaline. Rechargeable NIMH batteries are much more enviro-friendly, cost-effective and hold up in the long run far better than these lithiums and alkalines that you just have to throw away.

The Energizer L92 Lithium AA cell is a fantastic power source. For high-drain applications, it offers great advantages over ordinary alkaline cell and rechargeable NiMH cell. However, it is also very expensive as a disposable battery. So it is important to recognize the strength of L92, and use it only in applications that give you the best results. Otherwise you'll be wasting your money.

According to data sheet published by Energizer, the capacity of this Lithium AA cell (L92) is 1200mAh. This number remains nearly constant with load current. In comparison, the ordinary Alkaline battery (such as the Energizer E92) is also rated as 1200mAh, but only at a very light load of 25mA. At a heavy load of 500mA (typical for a P&S digital camera), its capacity is reduced to about one-third. The difference gets even greater at low temperature. At zero degree C and 500mA load, the L92 can provide about seven times more energy compared to the E92. This is where the marketing claim of "Last up to 7 times longer" comes from.

When used in a digital camera at room temperature of 25 degree C, the L92 is more likely to last 3-4 times longer than alkaline. This is enough to justify its price, which is also around 3-4 times higher than alkaline. However, in low-drain applications (such as smoke detector, wireless mouse or remote control) alkaline cells will last just as long at a fraction of the cost.

The L92 also contains much higher energy when compared to rechargeable NiMH cell such as the Sanyo Eneloop AAA. This is partially due to its higher terminal voltage of 1.5V, which is 20% higher than that for NiMH.
Energy stored in eneloop AAA: 0.8Ah * 1.25V = 1.0Wh,
Energy stored in L92 : 1.2Ah * 1.5V = 1.8Wh (80% higher).

Higher terminal voltage for L92 is especially advantageous in digital camera applications, because your camera flash will recharge up to 20% faster. On the other hand, it may create problems with some applications such as unregulated LED flash light. Higher than expected voltage will make the lamp burn brighter, but the excessive heat may also cause the lamp to burn out quickly.

Bottom line: If you need AAA batteries for a long hiking trip or for emergency standby, then L92 is obviously your best choice. For most other situations, I recommend using low self-discharge NiMH cells for lower operating cost.