Greetings potential laptop buyer. My humble opinion as a road warrior on his 4th laptop:
Make a list highlighting what you want the thing for. For me, the priorities were reliability/resilience (can withstand a fall from the aircraft overhead locker), warranty, battery life, weight. Speed not so much an issue for me (eg slower spinning hard drives have slower access times but use less energy). Maybe different if you want to play games and watch movies (when you need a widescreen). But then, why not buy a TV? PC/Issue depends on what you normally use - don't change the OS just for the laptop. Remember, laptops are moved and dropped unlike desktops (for which best bang for buck is the rule). My personal choice has been Toshiba and Thinkpads. Very unsexy but very relialble (even now Thinkpads are Chinese Lenovo). My last Thinkpad developed a power fault after 2 years use so I took it to the thinkpad centre at Taikooshing and they replaced the motherboard under warranty in 24h at no cost with questions - pretty good service.
Important: Whatever brand you buy, make sure it has a three year warranty because unlike desktops, laptops are prone to problems because they get moved. For example previously (may have changed) when I looked, Sony Vaios only had a one year warranty - useless. I need battery life so just bought a Thinkpad X60 that has no optical drive but I know it will work when I start my presentations...
You can check out Wanchai, Mongkok and Golden Center if you have time. But actually I found that the retail store Gome had a very competitive deal.