I bought this cyberlink remote about a year and a half ago, didnt work with XP media centre (unless you selected media centre from the menu or a shortcut). It subsequently stopped working for no apparant reason, so I looked for an MS official one (but they were too much money).
I bought the following one from Play when it was £6.99 not so long back, does an excellent job with the media centre bundled with Vista. Unfortunately, it's gone up to £9.99 now, but it's cheaper than the MS one and I'd still have bought it for the price.
http://www.play.com/PC/PCs/4-/335699...l/Product.html