Reddit mentions of Axiom Lasalle DLX Pannier Set (Black and Grey)

Most lights do a poor job of actually lighting your way and are more for increasing visibility to cars/pedestrians. I like to be as visible as possible, day and night, so I have lights (front and back) that are always on and like to wear high vis colors (day glow greenish yellow is my favorite).

Safety vests are super cheap and light weight but a lot of people don't want to look nerdy. I personally hate being hit by cars more than I care about what other people think of my fashion sense.

The right panniers will depend a lot on what you want to get out of them. A basket/crate might be the best option for you - you can throw your backpack or laundry/grocery bags in it. Def have bungee cords or a net handy to secure anything in the basket though. Saw a girl recently who was clearly on her way home from the grocery store. She hit a bump and her entire carton of eggs went flying out all over the road.

I'm a grad student with an office so I have an older version of these. They're great because they hold a lot and are essentially waterproof, but would be terrible to lug around all day.

If your current bike is in decent shape and fits you well it's probably worth upgrading. If you are really set on getting a road bike or there are any major repair/sizing issues with your current bike, there's no point in sinking more money into it. Be aware that a lot of road bikes don't have attachment points (called braze-ons) for a rack. There are racks that attach to the seat post, but those are limited in how much they can carry - groceries/laundry can be heavy.

One more thing I remembered... Fenders! Biking in the rain without them is rather unpleasant.