I started commuting back in 2008 after a trip to Japan. I stopped in 2009 and 2010 for various reasons but now I'm back. Here's my ride. I'd like to know what else I might need?

Bike: 2007 Trek 7000 Hybrid Bike
Bontrager Rear Bicycle Rack
Bontrager Interchange Grocery Bag Pannier
Cygolite Hi-Flux II 150 Lumen Light - bought used on Craigslist and it is the older model that has the water-bottle battery that lasts 6 hours on high.
Serfas SL-200 - 1 W light. Pretty bright but narrow. Use it as a backup
Trek Ion 6 that is attached to my helmet as a "see me" light.
3 blinkies. One is a 1W bright blinky that is in alternate flashing mode. The 2nd is on my seat pack and is steady. The 3rd is a cheap Bell blinky that sits low on the bike and I use it as a 2nd backup (seat pack is really my backup but I use it anyways)
Seat Pack Bellwether Aqua-No Rain Jacket - great windbreaker and breathable too.
Helmet

I commute about 13 miles each way to school. I usually have 20lbs of books and school stuff in the pannier. I carry 7lbs on my back via laptop messenger bag. The commute is early in the morning (6:30am and 8:00pm). The route is very hilly and traffic is usually low on the streets I go. Here in Louisville, KY there are several bike lanes and designated bike routes for saftey. Biggest worry are two 1.5mi stretches of mean hills on major 5 lane roads.

Total trip time for my 1st ride was 1hr in the morning and 1hr20min going home because my legs got so tired I felt like I was riding through sand.

I plan on adding another pannier for my laptop. Part of my trip is through a park that is PITCH BLACK at night and so I want something with at least 300 lumens.

What else do I need? Fenders? Definatly a new seat but the only brand my LBSs carry is Bontrager. How I wish for a road bike. But the streets have plenty of cracks and bumps in them.

And exhausted as I was getting home last night, it was worth every minute of it.