This is what I use:
$25.51 http://www.dealextreme.com/details.dx/sku.16538
It has a farther throw than a P7. I usually ride home after dark and part of my route is on an unlit MUP. This thing fits the bill perfectly.

And this:
$1.54 http://www.dealextreme.com/details.dx/sku.8274

And this:
$5.14 http://www.dealextreme.com/details.dx/sku.3499

and these:
$6.75 http://www.dealextreme.com/details.dx/sku.19770

Grand total: $38.94 and free shipping