Linux or Windows?
Either way use the 40gb for music and movies and split the 120 in half:
hda1= Bootspace if linux (100mb)
o/s and programs if windows (60gb)
hda2= OS Core and programs if Linux (60gb) (subpartitions recommended)
3dstuff and vid render space if windows (60gb)
hda3= If linux then this is 60gb for 3dstuff and vid render space
hdb1= Mp3s, Divx, Images....