Questions about server. Using Win 7

Currently I use win 7 for my server, as of now all I am doing in sharing the drives in the server which is connected via a wired gigabit switch. Its an older rig so it sips juice. What I have been reading about is WHS. What kind of benefits does WHS offer in that it would be reccomended over say a regular windows install? The only problem I am having now (which may be a simple setting) is that I want the PC to go into standby until I try to access the server. It currently stays on all the time 24/7

the drive usage how it can basicallty raid , backup features and so on, it is meant to be a server so it has extras in it say windows 7 doesnt, but if all you are doing is sharing files, heck you could throw windows 2000 on it or XP or any OS, since it isnt doing much of anything,