I research all of the time and let me tell you, researching for a laptop is HELL. The research I did is a bit outdated now, but it may still hold true. I'll describe a few of the things I learned in hopes that it will clarify things for you. This is by no means a complete guide to buying laptops though.
First, you have to consider what you want the laptop for now and then what you will want to use it for in the future (before you even look at laptops). Laptops do not upgrade, aside from things like the DVD drive and the amount of RAM. Your motherboard, CPU, and RAM speed and type are all locked in, so the only way to upgrade would be to buy a new laptop. For example, if you will want to use firewire in the future with a digital camcorder, but not now, then you will regret it when you need it.
I agree with z-component wholeheartedly. I highly recommend upgrading what you can from newegg rather than directly from the manufacturer (but make sure not to buy the cheapest parts, they will probably be crap). The parts you might want to upgrade include the RAM, CD/DVD burner, extra or larger battery packs - unless you can only buy the battery from the manufacturer! -, and probably a few other things that I can't think of right now.
There are at least 4 major things that have a big impact on the price of a laptop that are not at all obvious when you first start shopping for laptops (aside from functionality and it's brand, which is a pretty obvious cost). I'll try to list the non-obvious things in order of importance:
1. Where are you buying it from?
-Let me say this first. If you buy a computer from ebay or a third party vendor on amazon.com, you might get it cheaper, but you risk buying a faulty laptop and you might have to deal with shipping costs and having to rely on the warranty to get the computer fixed. If you look at newegg.com or go to Best Buy for laptops, you can't customize them and they might actually cost more than what you could get it for directly from the manufacturer (especially at Worst Buy.. Err.. I mean.. "Best Buy."). You also won't see upgrades (or downgrades) that the manufacturer's website has available. You also might get roped into buying an extra battery from Best Buy for $300, when it probably only costs $100 from the manufacturer and only $65 from an independent company. Best Buy is also notorious for conveniently forgetting to list extremely important pieces of information on their little computer info cards. I've seen laptops that didn't even list the CPU speed. It's really just downright pathetic. Unless you want an easy way to take the laptop in if there are any problems, buy the computer online. I also recommend staying away from ebay, because you have no real way of knowing where the laptop is coming from and what may or may not have been done to it.
2. Battery life
-A centrino will cost more than another computer which is 3 times as fast that has twice the amount of RAM and won't be dual channel, but it might get 6 hours of battery life instead of the much faster computer, which might only get 1 hour. This is very important if you want to use it for school. If you're using it for storing lots of files and typing things and you don't want to have to chain yourself to a wall outlet everywhere you go, a centrino becomes more attractive. You will also be very limited with your graphics cards too though. No centrino will produce much in terms of processing power or graphical processing powers. Most games will be out of the question. There are dual core power saving computers now though, but their battery life is shortened a little.
3. Size of the laptop screen.
-Very large ones are a lot more expensive, so are very small ones. The small ones tend to be slower machines though because they are limited to only the smallest hardware.
4. Weight and size.
-A heavy laptop that is big and bulky will cost less, but might be a chore to lug around school all day. It is likely to have a lot better hardware in it for less though. A mid sized screen is the happy medium here. I ended up with a 17" widescreen, which I am thoroughly pleased with. It's bigger than a 15" and still fits in my backpack, unlike a 19".
As a rule of thumb, before spending any large amount on anything to do with computers, including the computer itself, look for independent reviews (search on google for the reviews, or if it's on newegg use the reviews there). As a major rule of thumb, I suggest you completely ignore reviews where the person said "I got it and it rox!". Look at the reviews of users who seem educated and who have had the hardware for a while now. Even an experienced user who has only had the laptop for 1 day is very inexperienced with their laptop and their review can only contain value if they speak about how much value the laptop has based on it's cost vs "what it can do."
One last piece of advice: Never trust the people in the computer section at Best Buy. They are complete morons. Trust me on this one. They just want to make commission off of you and will tell you whatever they want you to believe. For example, I was told that my laptop battery would probably die within a year, so I should buy Best Buy's $350 1-year warrenty, because apparently batteries cost over $300 anyways. Yea right! I've had my laptop for over 2 years now, the battery is working fine. I bought a backup battery for $150 from the manufacturer, and that was the 12-cell battery, not the regular 6-cell battery, which was selling for $99 at the time. -- I've had equally hilarious encounters when they have offered their advice about hardware, ranging from graphics cards, to hard drives, to cd/dvd burners, etc. I'm not even sure if they realize how misleading the advice they give really is. Most of the time though, with the exception of the warrenty push, I think they are just really inept. Oh, I didn't buy the laptop from Best Buy and I no longer go there even for CD's.. lol
