Bike - type of bike won't really matter unless you're out in the country. Stop lights and traffic will limit your speed more than the kind of tire on your bike. I started on a road bike and switched to a hybrid. More upright position and better equipped for cargo means a more confident rider.

Safety - at the very minimum a flashing red for the rear and a solid white for the front, a helmet, and a hi-viz vest.

Clothing - normal work clothes this time of year with a hi-viz vest over top. I wear shorts and a t-shirt and change when I get to work, but it's so nice out right now that I barely sweat at all.

Kit - definitely a tire patch kit and frame pump. You don't want to get stranded when you get a flat.