Before you start using your camera
cleaning kit - rocket blower and lens pen
camera bag
extra batteries
extra memory card or two
lens hood if it doesn't come with your lens
In the near future
remote
tripod
filters = a good CPL and a ND4 and ND8 filter
M42 adapter
takumars
Maybe extension tubes and/or the Raynox
before you buy your filters you should make a commonality plan - buy filters for your biggest planned lens and step up rings (not step down) - you don't want to buy a set of 49mm filters and then not be able to use them with you new 52mm lens. and then buy another a lens with 62mm filter threads.