Hey Mike;
Great game. Great pick up.
LED's (IMO) are the way to go. Do some research as to what LED's "should" go where, though in the end, it is your preference as to what you like. Some of my friends HATE LED's...personally, I think they are awesome. If you are worried about skittling your machine up, stick with the warm retro LED.
As for parts...FUSES!! Replace the batteries with new ones. New balls. Spare rubbers (flipper rings included). Drop target bank (always handy). Flashers. Microswitches.
Good luck! This was one of my first machines. I have extra parts. If you run into anything you need, let me know so I can see if I have it!
Kyle