For what Apple sells, I'm happy with their lineup, it's an appropriate lineup and I'd say about 90% (if not more) of my friends and other people who want to go out and shop for a Mac are able to find something within the 5 different laptops they offer, two iMacs, the mac mini and if they hardcore need that much computational power, the Mac Pro.
The rest of them are hardcore technical users who need or want things that, well, demand a workstation or a different class of notebook computer.
I personally really love Mac OS and their desktop computers, but I'm not at home nearly often enough to justify owning a desktop computer -- the closest to a desktop I have is the fact that my laptop, which is not a Mac for a few reasons, has a docking station.
When I went laptop shopping, I went out with a fairly generous budget, I thought, of $2500, for the machine that would be my main computer for the next few years. I wanted a 2.53GHz processor, 4gb of ram and >300gb of storage, plus the ability to flip over to discrete graphics would've been a plus.
Apple will sell you that machine for $2499. And Lenovo will sell it to you for $1399, and you can use the remaining money on a docking station, second battery, bigger main battery, WWAN, carrier for a second hard disk, 1440x900 resolution on a machine smaller than 15-inches, and an external keyboard/mouse plus a spare power supply to use with the docking station.
Lenovo (And Dell, but I bought the Lenovo) had what I wanted at a far better price, and much of the software I use runs better on Windows (Office'07 vs Office'08) or needed to be upgraded anyway (AdobeCS3 vs AdobeCS4)
Not that I can't get a second battery for the MBP15, or just use USB peripherals (wwan/second-hdd) or use the new 24-inch cinema display as a docking station, but it the base machine itself was inexpensive enough that I was able to get those upgrades within my original budget.
The other important thing to me is that Apple's laptops tend to feel slightly poorly built compared to a Lenovo ThinkPad or Dell Latitude. The MacBook Pro may be sold as though it's a professional machine, but I have problems believing that it's actually professional-level hardware.