Just done exactly this.
At first I got hold of an IR repeater but once I got it I realised that the wire wasn't long enough so I looked at other things. (IR repeater for sale btw!)
I've ended up with a Harmony 895 (really please so far) which has an RF base/extender unit that you place into the cupboard where your devices are and it sends the appropriate IR signals.
Under my stairs (about 4m behind where the TV is mounted so the cables run straight through the wall behind the LCD, no cabling and no devices in my floating wall... looks lovely

) is a 360, Sky HD, amp and an HTPC.
I use the HTPC or Xbox for DVDs and it really isn't much of a hassle to walk the extra 6m to the cupboard in the other room rather than to the TV cabinet. How often do you watch a DVD versus the normal TV for the benefit of a clean look?