I've grown tired of plugging in HDs to my Macbook Pro all the time, so i made a fileserver where I hooked up my external HDs. Now I can access it from wireless too and when i'm not home
Speed via 1Gbit ethernet is kinda good for backup too.
The fact it's in my closet makes my desk a lot cleaner
The machine is a Dell Optiplex SX260 and the HDs are a LaCie NP 500GB and a Seagate FreeAgent 1GB. Too bad the SX260 only can hold ATA 2.5" HD, so i can't really put in much storage there.
I also have a LaCie D2 on my desk when I need a HD directly connected for video editing and such.