i don't think Apple buys such domains. There are active websites such as BuyiPhone.com.au for instance which rank well for keywords like "buy iphone". Please estimate.
I know a domain: wiinintendo.net and this one is perfect to have a lawsuit but it very much depends on a company and although wiinintendo.net is ranked #5 on yahoo and having 50k monthly visits, it still exists! i would say it very much depends if there are existing domains that have that TM and they are doing fine, then so can you. for instance eBay or Microsoft TM's are the worst case and this i wont argue but product TM's are more acceptable i think since you are promoting products, etc.