I bought a PS3 at the UK launch for £425 so I guess I might spend up to £500, but I don't think it should be priced that high. Most people aren't going to go for a £500-600 console and they leave themselves wide open to be undercut by the competition.
I think staying close to the PS4 launch price is a good idea but I really need to know more about the console. Its possible that Microsoft are considering a premium price sku selling alongside a budget one so unless Sony are going to do the same, it's probably a bad idea to price at the same level as the higher end model of the Xbox.