[John Lyon]

Personally, I'd get a tank bag so your backpack isn't too heavy. Extras: water, cell phone, extra layers (fleece, long underwear), tylenol, energy bars, extra motor oil, map or GPS, microfiber or cotton towel.

Also, for longer rides, I'm a believer in wearing bicycling shorts under everything. You didn't mention your pants, but jeans are not good if you're thinking of them. Beside lack of protection, you'll freeze if it gets colder.