The Stella is very popular here. It lights up well, but it's also very neat and lightweight and sexy-looking and many people like how you can take it off and use it as a headlamp for skiing or hiking. Excellent quality and totally waterproof casing and battery.

Mine is off for repair (turned my bike upside down and forgot it was on there) so I'm borrowing my dh's Magicshine. It's a cheapo version of the bright lights, and boy is it bright It's not by far as well made, but the light is excellent, the battery pack is good and the switch is actually better than on the Stella. The blinking function is positively fit-inducing, and gets me attention galore in roundabouts. But you have to be careful where you point the beam.

Taillight: I used to love the Superflash, made by Smart bike lights here, Planet Bike I think in the US, with one 0,5 W LED and two smaller ones. Now I have one that's even more annoying, with two 0,5 W super-brilliant red LEDs. They're so bright that on non-flash mode they light up the road behind me.

Oh, and please do remember side visibility. In intersections it's crucial to be seen from the side.