I ride w/ white/red CR2032 blinkies on front/rear of bike, 2 red CR2032 blinkies (main + spare) on rear of helmet, the above-linked light on front of helmet, a similar (old NiteRider MiniNewt) headlight on handlebars, Knog "Blinder 4V" 4-LED taillight on bike seat post, and TACX "Lumos" bar-end lights on the drop bars. Like herr-o, I'm a Christmas tree. I commute year-round, often on dark rainy pre-dawn mornings/nights, on city streets. So far, no driver has behaved in a way that suggested they didn't see me.
tacx.com - Bicycle lighting