I've read on Dave Ramsey's site (he's a finance guru that advises people to never use credit, though for reasons very different to my own -- I'm no follower, it's just the only place I've been able to find which discusses living without a credit rating) that it's generally possible to get a mortgage without a credit rating as long as you can prove you're a good risk in other ways (steady salary, large downpayment). I don't plan on ever having a mortgage in the US, but if I do I'll figure it out at the time.