These are the things I carry on my daily commute. They include:
1. Giro Atmos helmet. Ever since A, Ms. M and Mr. B have entered my life, I started wearing a helmet. Eventually I'll have to find ear warmers or a helmet that will cover my ears.
2. Topeak Alien Bicycle tool. It has 2/2.5/3/4/5/6/8/10mm Allen wrenches, T25 Torx, 8/9/10mm box wrenches, 14/15g spoke wrenches, tire levers,mini pedal wrench, Phillips and flat screw drivers, knife, bottle opener, chain hook, chain tool and even a nice nylon carry bag. It comes in handy when I have to make those minor adjustments.
3. CO2 cartridge and mini inflator, which has been a lifesaver a number of times. It beats trying to fill up a tire with a mini pump and you can find the threaded cartridges for fairly cheap on eBay, definitely buy in bulk.
4. Patch kit, I haven't used this on the road yet because...
5. I carry a spare tube and I patch my tire when I get home. Having a spare tire really saves time and a lot of headache.
6. Tweezers, for when I need to pull out a piece of glass that has lodged into my tire. Recently I've had two flats that were caused by a piece of glass and the only way I was able to take out that piece of glass was with the help of the tweezers. Sometimes my fingers are too fat for picking things out.
7. Tire lever, makes taking off the tire a lot easier. Actually I think its quite time consuming and painful to my fingers to take the tire off without a lever.
8. 15 mm wrench, even though the Topeak Alien Bicycle tool comes with a wrench, it is way too small and it is really hard to get leverage to loosen the tire lever bolt.
9. Glasses, just in case bugs or debris are flying in my face. Plus, on really cold days or windy days it helps my eyes from drying out. Here is Mr. B modeling my great $2 glasses from a drugstore.
10. My road ID, A made me get one of these for those just in case times. On my road ID, I have my name and my top three emergency contact numbers. I have never had to use this (knock on wood), but it gives A peace of mind, because if we ever needed to use the road ID, she would be the first to know and then Mr. B.
Though this seems like a lot of stuff, it really isn't that much to carry, especially since I carry it in my backpack and having all of this with me has saved me a ton of time and headaches.