I actually came up with these before I knew about the trick above (but I am not bitter). If you don't have a fangled HDMI(DVI) port then you could have a crack at my settings. On hooking my Raspberry Pi up into this socket everything ran swimmingly and and the edge of the screen lined up - magic. Hang on a minute, maybe not all HDMI ports are made the same. It was only since I've been testing the dual HDMI capabilities of my graphics card that I've had reason to try the other port and in doing so I noticed that the connection through the non DVI designated connector actually overscanned. My computer has always occupied this slot for no other reason that it uses ATi's special DVI to HDMI converter that magically passes through the sound as well and I've never had reason to change it - fit and forget. Simple I know, but it actually works a treat, my classic but still great by today's standards Samsung UE32EH5000 has two HDMI port with one designated as DVI.
You've probably been persevering down this road quite a while now so I'll spare you the basics and I will skip to a trick that may save you all the hassle Change to a different HDMI input on your TV It sounds easy but three Raspberry Pis in and I've only just found the technique that lets me fix it before my patience runs out. The usual bit of googling reveals that all you have to do is tweak a couple of overscan settings and you are good to go. If you've ever plugged a Raspberry Pi into a tv you've probably come across this issue - the displayed image either doesn't fill the screen or over-runs it.