Macbook Wireless Problem

I love my MacBook, I really do (although I am rather tempted by one of these). However, of late I have been having a really annoying problem it and my home wireless broadband.

I generally turn off the router during the night, to let it cool down and whatnot, then switch it on again at about 8 in the morning. The mac gets turned on then to deal with with any email etc that has come in, then I get the lad ready and do the school run. When I get home, the mac is fired up again and I start work.

Then we get to around three in the afternoon, when the Mac suddenly gets disconnected from the wireless, and any attempts to reconnect are doomed to ‘time out’. There’s nothing wrong with the router, and when I start up my lumbering Acer Aspire, which runs Ubuntu, it connects fine. If I am lucky, the Mac will be talking to the router again by about eight in the evening.

This is profoudly annoying. Does anyone know what might be happening here?