I recently got a new Apple "Alimunum" MacBook for work -- the very latest, top of the line MacBook model. It has all of the great specs -- 2.4GHz Dual core processor, 4GB RAM, backlit keys, blah blah. In most respects it is a really great computer, and I'm thankful that I have an employer willing to buy such a capable tool for my job.
For less money, however, Apple still sells their previous generation MacBook. Dave has already mentioned what a great deal it currently is. It has a 2.1 GHz dual-core processor and inferior graphics and worse battery life. It's a bit heavier, probably less sturdy, and of course not as cool as the latest thing. It also has at least one important feature not present in current model: a trackpad that doesn't drive me freaking insane!
The trackpad on the new MacBook is a classic case of Apple over-reaching in the form vs. function tradeoff -- trying to be just a bit too clever with a slick design, and accepting a non-trivial drop in functionality. The trackpad lacks a real button -- really the whole thing is a button. You can glide your finger around it and when you want to click, just press. Or, if your prefer, it can be configured to recognize a light tap as a button press. Actually, there's a whole host of various configuration options for two, three and even four-fingered tapping, pinching, dragging and perhaps tickling. Mostly all of those options are a waste of time and there "just because we can -- see isn't it cool!"

I wouldn't mind all of these extra bells and whistles if the basic feature worked well. Clicking the main button is in the top three most important tasks in using a computer. (Looking at the screen and typing on the keyboard are the other two -- and thankfully both old and new MacBooks excel here). On the old MacBook, I had a nice big trackpad, with an equally nice big single button at the bottom. Take your hand, and rest it neutrally over a square directly in front of you. Your thumb will be exactly where the button is, and your index finger will be a centimeter or two above it -- perfect for the trackpad. When it is time for a click, you have two choices -- either push with your thumb, or -- if you have "tap to click" on, just tap your index finger. Nice and easy. The "right-click" or secondary button click is either a two finger tap, or ctrl + button press. Also reasonably easy.
In theory, nothing has changed with the new MacBook. However because there's no separate physical mouse button, and because people still rest their thumb at the bottom of the trackpad (as is natural, and as we have been trained by years of Mac usage), they already have one finger on the trackpad. If you move your index finger around, the trackpad on the new MacBook will "see" two fingers. Ah, but Apple are so clever -- they have accounted for this by declaring that a certain portion of the bottom of the trackpad -- you know -- the part where the button used to be, is an exception. If you rest you thumb in this magic lower region, you can still move your index finger around on the upper part of the trackpad, and still click your thumb or tap your finger to click the mouse. Despite having two fingers on the trackpad, only a primary click is triggered. Magic!
Except magic absolutely sucks when it comes to computers if the trick doesn't work absolutely, unfailingly all of the time. You can see what's coming next: in the case of the new MacBook, it doesn't. It almost does, but every now and again I find that instead of moving the cursor, I'm moving nothing. Or sometimes my thumb comes up off the trackpad for a second, and I accidentally click when it comes back down. Sometimes despite moving my index finder around, the cursor barely moves. The problems don't happen all of the time, or even some of the time -- just occasionally, but it's frequent enough to make me unhappy. There was a recent software update for the trackpad which I understand fixed some problems -- just not mine. The problems get even worse if I turn on the "one finger drag" option in the Trackpad system preference panel. That option is misnamed -- it should be called "randomly initiate mouse drags until your brain leaks out of your ears."
Where is this "magic thumb line?" Somewhere -- who knows. If you're in the market for a new MacBook, get the older, cheaper model -- add in a ton of RAM, and be happy. It's a great computer.