If you want something with a nice wide viewing angle, try the 7-LED blinkers from both planet bike and vistalite; the ones that look like little pods.
I had one from planet bike that had 7 LED's, 5 facing rear ward and 2 angled about 30 degrees to the side. The cover dispersed the light so that it was pretty much viewable from an arc of about 160 degrees.
The new cateye blinker's nice cause it runs on AA batteries and is pretty bright, 2 rows of 3 LED's with focusing lenses out back, 2 sets of 2 LED's firing sideways.
I think you have to aim for recognition too; brightness isn't the only factor. Drivers also have to recognize that you're a vehicle on the road.
Here's my hypothetical no expenses spared super dork setup.
I'd have two niterider 19-LED clusters ($120) out back mounted sideways about 10" apart shining 5 degrees sideways on solid mode along with two performancebike 3-LED flares (red and white) ($40) next to each other in between the NR's in blink mode.
Then a cateye TL-LD 1000 blinker on the back of my helmet ($30) one row solid, one row blink.
Then I'll put an amber LED blinker and a red blinker ($60) facing rear wards mounted 8" off each side of the seat stay/rack on an extension with the red in solid and amber in blink mode.
I'd have a nightsun dual 13watt HID + 20 watt halogen lamp up front hooked up to a custom 10000mah lithium battery pack ($500) and two performancebike flares ($40) on my helmet, white and red to bean drivers at intersections.
There'll also be an amber blinker ($30) on solid mode firing sideways mounted on each side of the front fork.
Tack on a reflective safety vest for that touch of passive visibility and I'll be more visible than 90% of the CARS out there.
You can have all that for the cost of less than a single lupine edison HID headlamp.
