I got a couple of those $3.81 tailights from Performance a couple years ago. They didn't last, so baby them.

We are using Cateye LD1100 blinkies now, and I like them a lot. I left my LD600
on and keep both going. 3 rows of LEDs blinking side to side is very effective and the batteries last a very long time. If it's dusk or dawn I use one the brighter flash modes, and again, the combo is surprisingly effective when seen from a distance.