There seem to be several LED conversions for the AA Maglite. I started with the standard 3 LED replacement which is OK, but you loose the ability to focus the light beam. Based on my experience with the 5W conversions for the D cell Maglites (they are amazing! Check eBay for Terralux TLE-6EXB), I have ordered the same bulb for the AA (Terralux TLE-5EX), although there are a couple of slightly lower power version . I will let you know how it performs when it arrives if you are interested. BTW, although the delivery takes longer, buy from the US - the bulbs are half the price...
Andy.