Dell
Note: I've been in the computer industry since I sold my first program at age 15. I may be a low-hour pilot at this point, but I have a zillion hours in front of a computer, have worked at large companies and small, and have built and sold my own software company.
I feel fairly confident when I say:
Right now, today, you can't go wrong with a Dell.
At various times in history, other companies have held this title. And tomorrow, things may change. But right now, Dell is it. Don't bother with Compaq, IBM, Gateway, etc. If you're looking to purchase a PC, buy a Dell.
Some folks have recommended an Apple product. They're just fine, if you know exactly what you want and why you want it. There are perfectly valid reasons for purchasing Apple...but you darned well better know what those reasons are.
For 95% of the world who wants internet access, email, word processing, a couple games, perhaps a spreadsheet or even a minor database or two, you want a PC.
You don't want Linux unless you're at least 1/2 way to computer guru (think instrument and commercial rated, working on your CFI...but with computers).
You don't want Mac if you don't have a good reason for wanting Mac. That is, there are specific reasons for wanting a Mac. If you don't know what those reasons are, then you want a PC.
While there's nothing wrong with Compaq, IBM, etc. in PC land today, right now you can't go wrong with Dell.
...Dave