Lights are important things to have on a bicycle if you plan on doing any riding at dusk or after dark. I'd prefer giant, pulsing strobes that would cause F/A-18's to try to land on my luggage rack, but I had to settle for multi-LED units.
And lor' bless the lowly LED: Before they became cheap and plentiful, you needed a dynamo on the bike, because a light any brighter than a half-dead firefly would suck the copper right out of a battery in about an hour.
I know this sounds silly to those of you who have only two thumbs, but I was inordinately happy when I got both lights mounted and functioning on my bicycle yesterday, and even after pedaling like mad up and down the rutted gravel alley, they remained attached and pointed in the proper direction. I rode to Fresh Market with roomie last night in two-tone, strobing splendor...
(...and a general hat tip to Xavier and all his mad bikie linkz.)