A couple of times this week I've had to commute home as night was falling or later still. I have a little light for the front which I expect to keep as a blinkie, and I have one of those new, cool Cateye put-it-anywhere red blinkies for the back (put it on the seatpost in seconds). I commute within 100% Manhattan, currently a mix of Greenway and streets. The streets are better lit, but require more visibility than the Greenway, so I don't think there's much of a difference there with respect to lighting needs.
What should I do to equip myself for the inevitably darker commutes later this year? I haven't year-round commuted on a bike since '96/'97 so I'm a bit out of the loop when it comes to more powerful lights. Plus I have "special needs" as a folding bike rider (have to be able to instantly remove any hardware so I can fold the bike!). I cruise on my folder on the flat sections of my ride between 28-32km/h (clearly speed affects choice of lighting).
Any suggestions? Note that my folder doesn't have any braze-ons for a bottle cage, but I do have a tricked-out backpack which maybe could hold a battery.