Why Windows2000, remove it.
So you have 240 GB HD Capacity. the partition take more then 15/20 GB, then you have 220 GB.
Importent :
For 7 --> 30 GB enough.
For vista --> 40 GB.
For XP --> 20 GB.
So, 30+40+20 = 90 GB Gone for 3 Windows. Still 130 GB left.
So, 5 pertition are good for you.
Like this : (C)20 GB--> XP
(D)40 GB--> VISTA
(E)30 GB--> 7.
(F)70 GB--> Software.
(G)60 GB--> Music & Video.