I would go a bit tangentical on this and suggest an Evoke Pure Flow DAB/FM/Internet/streaming radio with it's matching (optional) S1 Flow speaker.
Not too expensive (£150 + £35), wirelessly streams music from your servers and plays internet stations wirelessly (no computers need to be powered on for that) and gives you easily searchable 'listen again' facility. It is 802.11g/WEP/WPA/WPA2 compatible and looks pretty good in solid lacquer black. (Easy to clean/polish/wipe chicken juice off!) Oh yes, it also has DAB and FM - of course - and full timering/alarm facilities.
Sounds great (even without the additional speaker).
http://www.pure.com/products/product.asp?Product=VL-60896
And you will not need the Airport Express with it (one less 'box' and one less plug) in the kitchen. You can use that somewhere else instead.
I bought it to go in the kitchen but I am enjoying it so much I am reluctant to let it go out there.
Just an alternative thought.