what update do i install on my ipod touch 4g using windows 7 64bit

I think I am going to have to do some research on all this **** OS's and versions and software not to mention firmware or hardware or the many other attributes that come along with this amazingly powerful device called my ipod touch. got to love this magical machine that apple created. its insane i should not be this lost when it comes to all this tech crap. ok i guess i just need to get back into the groove of it. wake up outta my fog. but until i do....does any one know what update I am suppose to be installing on my ipod touch 4g? i am using windows 64 bit