Pilot 16,
Assuming that you'll be renting the airplane, I would recommend a standard AA Maglite (w/o filter) for pre-flight inspections. If you own the airplane, then get a two cell D Maglite that you can leave in it. Try to get this in a silver colour rather than basic black, since the latter is easier to lose on a dark night.
In addition to your inspection light, you'll need a small, red or blue/green filtered light for cockpit use. Something that you can wear around your neck is best, so you'll always be able to find it.
A filtered AA maglite would work but would not be my choice: it's really too big and heavy for the purpose. A better choice is the #1930 L1 LED Light from Pelican [
http://www.pelican.com/main.htm] that comes equipped with a lanyard and is small and light. You can grip it in your teeth if you have to. I've had one since I stareted night flying, and swear by it.