It's been about six months since my last laptop buying guide. Sounds like a short time, but you can't stop innovation in this market, and you'd be surprised how much has changed in the last few months alone. I've also been surprised how many emails I've received in recent weeks asking for laptop purchasing advice, so it seems time for another update on what to look for in a laptop.

Here's what I advise looking for in a new notebook purchase.

• CPU - I wouldn't bother with any chip other than an Intel Core 2 Duo. Don't get suckered into getting a cheap Celeron machine, and don't go for an AMD system either. The speed of the chip isn't terribly important, but you do want to make sure you're getting a "Santa Rosa/Merom" system, which is more future-proof than older models. How do you know if you're getting a Merom CPU? Just check the chips listed in the Merom section on this Wikipedia page. Just match up the model number on your laptop of choice and see where it falls.
  
• Memory - 1GB is a bare minimum today, but it should suffice for most laptops.
  
• Operating System - It's hard to find a PC without Vista preinstalled on it right now, but it can be done. If it's available as an option, I'd choose XP over Vista, no question. Of course there's always the MacOS and Ubuntu, too.
  
• Hard Drive - While you can get hard drives with no moving parts now (called SSDs, or solid state drives), they are so expensive it doesn't make sense to do so. Stick with an old-fashioned spinning-disc hard drive. Capacities haven't changed much lately. While you can get up to a 250GB notebook hard drive, most come with 80GB as a default, which most users will find big enough. Upgrade according to your needs.
• Optical Drive - Both Blu-ray and HD-DVD are starting to make a splash on laptops now. Note that HD-DVD laptop drives are read-only; if you want to write to high-def optical media, you'll need the Blu-ray option that some vendors offer. I doubt many users need this much high-capacity optical storage, though. And there's no real advantage to watching high-definition DVDs instead of regular DVDs on a tiny laptop screen. I'd just stick with a dual-layer DVD-RW drive for the time being, at least for another six months.
• Graphics Card - With Vista, it's more important than ever to invest in quality graphics. I wouldn't recommend any integrated graphics solution. You'll be very disappointed with the experience under Vista. That said, few notebooks offer much of a choice when it comes to graphics options, so juice it up as much as possible. Upgrading to discrete graphics from integrated can be as inexpensive as an extra $99, but it'll make a world of difference in your daily computing.
• Screen - Nothing much changing here, except that LEDs are starting to appear as backlighting instead of fluorescent tubes. This means you get a brighter screen and lower power consumption, but the difference is not dramatic on either count. Don't hold out for LED backlighting and choose instead based on how big a screen (and how much weight) you're willing to carry. Laptop weight has not really changed at all lately: Expect to carry 8 pounds and up for a 17-inch system, 6 to 7 pounds with a 15.4-inch machine, and as little as 3 pounds with an ultralight.
• Wireless - The Santa Rosa chipset I mentioned above puts four flavors of Wi-Fi, 802.11a, b, g, and n into your notebook. You definitely want this: Nearly all upcoming Wi-Fi hardware will use 802.11n in some form. Wireless WAN (WWAN) is another option that many vendors now offer. Want to get high-speed access away from a Wi-Fi connection? Now you can do so without a bulky add-in card. Add it if you want the feature and can afford the monthly service fees.
  

That's about the lay of the laptop land today. In case you're wondering, Macs have seen only modest refreshes in recent months. If I was getting a Mac, I'd make an exception to my above rule and wait for the new LED-backlit models to show up (since that will be in a matter of weeks) and, if possible, until 2008 when the new MacOS arrives. It would still be OK to purchase one today, but I think you'll get a better deal if you wait a bit.

As always, feel free to send me specs or a link to the laptop you're considering via email and I'll weigh in with an opinion. Happy shopping!