I don't mean to cast any doubt over your father's account, but I'm just curious, what issues did he have with his Dell? I've had my current Dell Latitude for just over a year with no problems (my business machine). Additionally, I still have an old Inspiron E1405 that's over 4 years old and it runs Windows 7 like a dream. I bought full protection on it and just a few months back the hard drive finally died. Dell overnighted me a new LARGER hard drive. They're not always the greatest to deal with over the phone unless you have a corporate support plan, but I love their online chat tech support.
In any case, if support is your top concern, I'm not their biggest fan, but apple is the way to go. It's nearly 100% US based support and pretty comprehensive since they also make the operating system. I recommend them to all my non-tech savvy friends who seem to break computers just by turning them on.