Something happened the other day that has me thinking we're really getting into overkill here. I was commuting at about 6:15am and ahead saw a very bright LED blinkie. The rider was on the other side of the road (4-lane divided road, with bike lanes), on the sidewalk (as I later discovered) and was well over a quarter mile ahead of me. It turns out it was an older woman on a cruiser-style bike. I crossed the road and came up behind her and (in a friendly sort of way) asked what kind of tail light she had. She told me she wasn't sure, that she had just gotten it at the LBS. I told her it was very bright and she thanked me fpr the feedback. I looked closely as I passed and thought it was an LD600. Anyway, that thing was bright and very noticable from over a quarter mile (and the other side of the road) and it's not even a top of the line model.

My point is that from a practical standpoint all of the lights discussed here are probably more than you need. Buy what you like.

Personally, I use an LD1000 with the 2 rows of LEDs set so that they're flashing different patterns. On my warm weather commuting ebike I also wired in a 12v LED third brake light from JC Whitney. The cooler weather commuter (Bianchi San Jose) gets by with just an LD1000 but once the LD1000 replacement comes out I'll either add one of those or a SuperFlash, for redundancy.