Updates from nVidia are for your display and graphics cards. Often these need not be installed unless you are an avid gamer, in which case they may well help some games run better.
The Vista update is for the 'Help' facility within Windows which can be of value in the event of a problem.
The last is a driver update for the ethernet adapter within your motherboard.
Whilst all four are optional, I find that installing such updates may make the PC run smoother/quicker and may prevent other updates clashing with some software. Certainly some are quite large, but can be downloaded/installed when you have little to do.