Are you one of the many people who will be buying a computer in the next couple of months? If so, then you need to determine what to buy. There are all kinds of specifications out there, but what do they mean? Which ones are important? Don't worry, I am here to help!
The first thing to determine is if a desktop or laptop computer fits your needs. This used to be a much easier question to answer, but as laptops have gotten more powerful, it isn't as easy to figure out anymore. Let's examine a couple strengths and weaknesses of each:

Laptops
Strengths: portability, ability to take the internet with you wherever you go
Weaknesses: not as powerful as desktop hardware, very limited upgrade path, generally more expensive for comperable hardware, harder to fix, high risk of theft

Thoughts: Laptops have come a long ways in terms of power and capabilities and that is a large part of why they have outsold desktops the past couple years. With options to get the internet through your cellular provider, you truly do become untethered. The downside however is that once you buy a laptop there is very little that you can do to upgrade them. They do carry a high risk of theft (600,000 just from airports this year), and they are nearly impossible for the average person to fix on their own.

Desktops
Strengths: powerful, typically larger monitor, better upgrade path, generally easier to fix, usually cheaper for comperable hardware
Weaknesses: not portable at all, large, not as energy efficient

Thoughts: The lack of portability is a great hinderance to our increasingly connected lives. The ability to upgrade nearly every aspect of your machine, the larger monitor, and price should still weigh heavily in your consideration for which to purchase.

After careful consideration, you have made up your mind as to which suits your needs best, right? Good, but that doesn't get you out of the water yet. What do you look for when you go to purchase one of these machines? Let's examine them alright?
Across the board, there are a few things that you want to consider no matter what platform you are looking at. The CPU, the RAM (memory) and the hard drive (storage space) are the big three. Focus on those, and on the laptop side, you may also want to look at whether or not it has a discrete (seperate) graphics card.

Laptops
These are the things that you should look for in any laptop that you buy currently:
Intel 6000 series CPU (It will say something like Intel Core 2 Duo 6500 for example)
3 GB or RAM (no less than 2 GB, but 3 GB is easy to find and there is no real price advantage)
250 GB hard drive (if you need more storage, you are better off with an external hard drive)
Look for these specs or higher
All laptops nowadays will have a DVD burner, webcam, and wireless standard.
A laptop with these specs will cost $550-700. Do NOT pay more than this.
When you look for a laptop DO NOT buy one with specificatons less than these. There is no advantage to doing so. If you follow that guideline, you will be able to have a fast enough machine to use for a few years. If you short yourself, then you will find it to be outdated by this fall already. I have been a big AMD fan for years, but they do not have a good mobile CPU offering at this time. Going with an Intel will be faster and net you longer battery life.
Accessories: wireless mouse, carrying case, protection plan

Desktops
The guidelines for a desktop system are much harder to pin down due to the limitless variety of configurations, but considering that you are an average home user, you should look for the following:
Intel 4500 series CPU or AMD Phenom X3 or X4 CPU
3 GB RAM or more
500 GB hard drive
Discrete graphics card (any one will do, unless you are a gamer)
19 inch or larger monitor. 22 inches is the sweet spot right now
Look for the above specs or higher.
Any desktop that you buy should include a DVD burner, keyboard, speakers and mouse.
Accessories: battery backup

Holy cow! You now have your new computer and its a speed demon right? Nice. Do you want to keep it that way? I have two tips for you:
Run PC Decrapifyer. This program will get rid of all the junk software that came pre-installed on your machine. And its free!
Go visit my page on software to prevent problems. Not only will this help you prevent problems, it will save you money!