I agree with this. I have a bunch of crap that I bought thinking it might be needed and found most of it to be a pain to put on, find its not really needed and then having to take it off again...

what do I have on the bike?

+ toe clips (I prefer them to clipless and now just platform feels weird to me now as well)
+ a Bell handlebar bag that I got from walmart (best bag for the money around 10 bucks)
- which contains: 2 tubes, patch kit, tire levers, chain tool, multi tool (bell)
- my wallet, keys, and cell phone
- and it has some room to spare....

+ a Bell cycle computer that I got from walmart (best computer for the money, it cost me 10 bucks)
+ cree 1200 lumen light with rechargeable battery (great buy off of amazon for $20)
+ because I use the bike for commuting, I need something to carry stuff:
- avenir seatpost rack
- planet bike day trekker panniers
- roswheel trunk bag
- as a side note, a simpler setup would be a rack with a wald basket and backpack...
+ road morph tire pump
+ 2 water bottle cages
+ some generic blinking tail light (got from walmart, it has multiple blinking modes)