I love my LM303. It's a small, simple (2-stage reverse clicky), very bright SSC pocket flood. At ~$35, I think it's a great bargain. If you strongly prefer an AA light, its brother, the LM 301, is also nice but lacks the output of the LM 303.
The LM301 is actually more flexible than the LM303 -- I have both. I just bought another LM301 in fact. And it looks like Lumapower has gone back to the LM31 and LM33 designations by the way.
The LM31 on 1.5v AA has a very low low which I find terribly useful for reading and navigating around the house. The LM31 on 1.5v AA has reasonably bright high on 1.5v AA -- about 90% the brightness of the LM33 on 3v CR123A by the specs. However, the LM31 has much longer run times on 1.5v low (up to 15 hours) than the LM33 on low (4 hours) which must use 3.0v or better CR123A size battery.
If you're a brightness freak, both the LM31 and LM33 can run on 3.7v rechargeables. The LM31 can produce the same levels of output on a 3.7v 14500 that the LM33 can on an 3.7v RCR123A.
The only advantage the 33 has over the 31 is that it is a little bit shorter.
LM31 pros:
1.5v and 3.7v options to choose between runtime and output
Very low low output on 1.5v with very long runtime, excellent for reading
Runs quite well on alkalines -- good emergency choice
LM31 cons:
longer form factor than LM33
LM33 pros:
shorter form factor and LM31
LM33 cons:
Low level still relatively bright and not as useful for reading
Longest runtime still significantly shorter than LM31