I also ride throughout the year, including in the winter months when it's dark by the time I leave the office and rains a fair bit. This is the front light on my main commuting bike: http://www.wiggle.co.uk/cateye-hl-el...k-front-light/ It's a Cateye and is bright (3 leds), small, light and the batteries (2 AA) last for ages. It works well in a city environment where there are a lot of light sources already and the main function of the light is to draw the attention of drivers to my presence. I have it on the flashing mode most of the time. I'm not sure that it's bright enough to light up the road ahead sufficiently if you're riding outside town though. It doesn't say anywhere that it's waterproof but I regularly ride in the rain and this hasn't been a problem yet.