I'm not convinced that painting the bike dayglo would do much to improve its visibility. Really, there isn't much bike there; it's mostly air - unlike, say, a car - which is solid.

You, however, can and should wear something bright. I've been seeing a lot of the Alert Shirts yellow t-shirts on the bike paths here lately, and am impressed with just how visible they are. Ummm, URL: http://alertshirt.com/

If you ride at night (try it, it's great) you need lights. Think Christmas tree, think the guy at Christmas whose Christmas lights dim the lights all over town when he plugs 'em in, think new saloon, think new saloon at Christmas... you get the idea. When I get extra money (??!) I plan on putting these on the bike: http://www.fossilfool.com/down-low-glow.htm