Rear bike light

I already have  a basic cateye flashy one which i reckon does the job of alerting drivers when I'm in shade parts of the road during the day.  But if I head out at night it'd be nice give myself the best chance of being seen.

So, any suggestions?  I think it'd prefer something quick to mount and rechargable.  Weight isn't an issue obviously!  I already have exposure lights for the front of the bike.  I was thinking of getting a white light and customising it to emit red light if that'll be a good solution to create a nice pool of red light (i was thinking it'd be good to have a pool of light on the floor as there's not so much to be gained from purely blinding the driver behind!).

Thanks for your help.

cougie - well i enjoyed my one bike ride, so we'll see.  got a couple of weeks off to relax and get the miles in.

thanks for the smart light recommendation, i'll take a look.

is it the superflash one good?

Smart Superflash Ultra Bright Rear LED Light

on today's ride i was a little worried when i headed into forest sections on the busy roads.  would be good to ahve a decent light soon.