If you do decide on two cameras, the NYT just did their "best under $300."

For on the bike, I've got a Fuji Z33WP. Not the greatest thing in the world, particularly in low light, but waterproof for right around $150, and much more compact than the other waterproof P&S cameras that were available last year. That means I don't have to carry it in something sweatproof and difficult to access. It's fine for landscapes, group shots, and most everything I'd want to shoot from/near the bike.