HP hands down
Ten years ago IBM (now Lenovo) was Alpha male, they were untouchable, quality was sublime, the ThinkPad developed cult status, Dell however had their classic inspirons with high res UXGA screens, there were issues around their support and their firmware proplems but they worked (most of the time).
Today only 3 names are at the top, they are HP, Asus and Acer. HP imho is the heir to IBM, they have a corporate history involving HP-UX to business class printers, their reliability, quality is top.
On price Acer offers the best options, on netbooks its Asus although their high end laptops are unique and stylish but all this depends on you, the user, are you a business user if so its gotta be HP, if your a gamer I'd go for Acer although others like Alienware are good they don't match Acer for reliability or quality.