Can take off a few things if you're not in good shape yet.

- 1 water bottle and cage
- pedals shoes if you don't have the cash yet. Just get cheapos.
- ride without gloves and see if you need them. I personally don't have any desire to get them but I have friends that felt they needed them.
+ presta valve adapter
- repair kit if you won't get stranded from a flat atm
+ sunglasses if you don't have a pair already

Jersey you'll prolly eventually want one. I use dri fit shirts atm. I kind of want a jersey just because they are longer in the back.

But ya most stuff depends on you and how far/ much you'll be riding at first and your budget.