Do not buy a low-end Dell. Their quality has been eroded seriously in the price wars, and they’re trading on a reputation that they no longer deserve.
Unless you’re going to be carrying it someplace more often than using it at home, don’t get a laptop, either. It’s a major pain in the ass to do anything to these systems; the miniaturization involved means very few upgrades are possible, and repairs are expensive and time consuming.
Your best bet, IMHO, is to find a local store that will let you select all your components, and have them build it for you. Local tech support makes a huge difference. Check their rep with the Better Business Bureau first, then talk to a salesperson there. If you get treated well, like what you hear, and can take an estimate home and research some of the components, you’ll end up with a serious kickass system that will beat the living snot out of any name-brand system out there.
Oh, and Compaq, Hewlett-Packard, and Gateway are the current pseudonyms employed by the Triumvirate that Rule Computer Hell.