If Christmas were six weeks later this year, my annual how-to-buy-a-computer column would be a lot easier to write.
That's because every PC on the shelves right now uses a version of Microsoft Windows that will be gone by Jan. 30, when Microsoft releases Vista - the latest update to its flagship operating system.
Normally, I'd advise readers to wait till the new version of Windows comes out. But 'tis the season, and some shoppers need a PC right now. Still others think this is a great time to pick up a bargain computer as retailers sell off their inventory of perfectly good machines running Windows XP or Media Center Edition - both of which are debugged and reliable.
And prices are down. During the week after Thanksgiving, the average laptop sold for $708, down 17.3 percent from last year, according to Current Analysis Inc. The average desktop sold for $464, down 5.9 percent.
With those figures in mind, here's my annual, component-by-component guide to buying a PC.
Vista compatibility: Many manufacturers are offering free or low-cost Vista upgrades to holiday season buyers. If you think there's a chance of upgrading to Windows Vista, make sure the PC is labeled as Vista-ready. And make sure it's ready for the version of Vista (basic or premium) that you expect to buy.
Processor: Also known as the central processing unit, or CPU, this is the heart of any PC - the chip that does the real computing. Intel is the biggest supplier, but many consumer PCs use chips from Advanced Micro Devices (AMD). They'll all run the same software. Within a brand, the main differences involve the model designator and speed, measured in billions of cycles per second, or gigahertz (GHz). Faster is better.
You find more than normal variation this year as Intel shifts to a new line of chips called Core 2 Duo and manufacturers dump older models. Dual core machines split processing chores between two processor cores - a tactic that accelerates multitasking.
Older Intel desktop models may still use the Pentium 4, while laptops use the Pentium M, or first-generation Core Duo chips. Low- end machines will have Intel Celeron chips - a bargain-basement version of the P4.
At the top of the line for AMD are the company's Turion and Athlon 64 X2 processors, which also have dual cores. For the time being, Intel's fastest are a little faster than AMD's fastest, which matters if you're calculating hyperspace travel routes or playing high-end shoot'em-ups.
For high-end gaming, video editing and Vista Premium upgrade capability, stick with an Intel Core 2 Duo or high-end AMD chip. For basic computing under Windows XP, virtually any processor will do.
Internal memory: Also known as Random Access Memory, or RAM, these chips store programs and data when the PC is running. The more RAM, the faster and more reliably your PC will run. In fact, adding memory is often better than buying a slightly faster processor. The store can install additional memory before you leave - often for the cost of the chips alone.
Memory is measured in megabytes (millions of bytes or MB) and gigabytes (GB). For Windows XP, 512 megabytes of memory will usually suffice, although a gigabyte is better. For Vista, Microsoft has upped the ante to at least a gigabyte, and the wise guys I know are urging 2 GB for Vista Premium. This will bump up PC prices.
Hard drive storage: Your hard drive stores programs and data permanently and shuttles information back and forth from your computer's memory when it is needed. Capacity is measured in gigabytes, or billions of bytes.
Hard disks are so cheap that it hardly pays to economize here. In fact, few consumer desktop machines come with less than 80 GB, with most in the 160 to 200 GB range. Laptop makers are a bit stingier, typically providing 60 to 100 GB.
The only reason you'll ever need more than 150 GB is if you want to store lots of video. In that case, buy a computer with a drive in the 200 to 400 GB range. If you want still more space, external hard drives that attach to a USB port start at $150 for 300 gigs. They're good buys.
Video: This is where future Vista capability may require a decision now. The video adapter determines what you see on the screen. For basic, pre-Vista computing - which means anything less arduous than high-end gaming - the Intel-based video adapters in most entry and mid- level PCs are just fine.
However, to enjoy gaming or savor the fancy graphics of Vista Premium, you'll need a dedicated graphics adapter with its own video memory. Most of these have graphic chip sets from nVidia or ATI, and that will be noted on the sticker.
Vista premium requires at least 128 MB of video memory, but gamers will need even more power and twice that much video RAM. If the desktop machine you like doesn't have enough video horsepower, you can buy a plug-in video card after the fact. But with laptops, shop carefully now - you're pretty much stuck with what you get.