If you are looking for a nice bright daylight visible but not too pricy tail light, I would suggest the Serfas UTL-6 Thunderbolt. Yea it's a bit more than the typical AAA blinkie, but has a number of pluses. It's USB rechargeable, I take mine into my office at work and charge it every day (comes off in 2 seconds) and it's much brighter (subjective yes but obvious IMO), than the AAA blinkies I had. All three AAA blinkies I had (Performance, Planet Bike, Blackburn) had plastic mounts that suddenly snapped as I rode, and I lost the blinkies. As the whole thing comes of in a moment (no tools), it is easy to take from bike to bike, and as it weighs almost nothing, I've been using it on my road bike too, and it does not look too geeky. It can be strapped just about anywhere, I mount mine low on the seat stay. It could probably be strapped to the back of a rack, provided the location is not too thick for the mounting strap to wrap around, and be off in a moment and tossed into a backpack or into the pannier and taken with, one less thing to get swiped. I also use a Dinotte 300r which is brighter, but at a cost. The two together make me very visible in the dark, and catch peoples attention from a distance even in daylight.

If any commuting is pre-dawn, I would suggest some good reflective tape. Been using tape I bought here http://www.reflectivelyyours.com/generic156.html and some Nathan stuff I got at REI. Put some on the seat stays, chain stays, fork and down tube, and put the Nathans tape on the helmet. Also bought some 'Lightweights' reflective tape that is wrapped around each wheel spoke. Takes a little time to put on, but it provides great side visibility in cross-traffic in the dark. I also wear a Nathan mesh reflective vest and leg bands.

Another neat light is the Fibre Flare bike light. Been using that as well, strapped on the downtube, as a side visible light. Wish it was USB rechargable (uses 2 AAA), and quicker to get on and off but the batteries do last quite a while.

Up front, I use a Nightrider Mininewt 600 all in one light. The middle brightness is fine in the dark, it has a blink mode for daylight, and again I can charge it at work as it's USB rechargeable. I also use a helmet light (L&M Stella 150 lumen) that I can 'point' at inattentive drivers.

As you can guess, I spent quite a bit of time researching and setting up my lighting as my winter rides are in darkness, with the first mile or so, with no streetlights, and the rest, on urban streets where I am competing with storefront lighting for motorist attention. I pass a ghost bike every day, so I'm always thinking of ways to stay safe. Maybe I went too far, but co-workers say they can see me from a mile away.

Congrats on the new commuter and be safe out there!