Building your own, with hand-picked, quality parts, is really the coolest way to go, but it can turn out to also be the most expensive. Plus, you'd have to keep track of the invoices, dealers, and warranties for every individual part. Unless you're really into it, this may not be the best way to go.
I do computers for a living (10+ years now), and as my main hobby. Over a decade ago I started in computers as an avid hobbyist/enthusiast, then student, then professional techie, then team leader, now IT Department Manager for 7 years. I currently have 4 hand-built PC's (at home) plus 4 laptops and a Dell PC for my wife. 2 are over-clocked, SCSI RAID0 hot-rods, 1 has dual processors, terabyte RAID5 array, and 3 operating systems. At work, I directly support ~50 high-end corporate servers and 300+ desktops and laptops, many of which I built 100% from purpose-driven hand-picked parts. Indirectly, I support an additional 150 high-end corporate servers and another 700 desktops and laptops, of all makes and models. If anyone else here has experience and credentials like that, you may want to strongly consider their thoughts.
Believe me, I've been through this many, many times for friends, family, and coworkers. I've done the research and backed it with experience, as to provide the best quality recommendation to someone asking me. Obviously, you did not ask me and it's important to remain cool to your online friends, so take my recommendation as you wish.
Dell's don't **** any more than HP/Compaq, Sony, Gateway, or other popular mass-manufactured system. They're all basically assembled of the same or similar parts, in almost exactly the same way. Better PC's will come from the likes of Alienware (although they, too, now have "budget" models), Voodoo, Falcon Northwest, etc. Worse will come from some like Acer.
The benefits to going with a mass-manufactured system include lower overall price, one-stop support and warranty, and you don't have to know anything about putting a PC together correctly.
If you do go that route, you may want to be sure the case has full-sized expansion bays and an AGP or PCI-ex slot for video card upgrade. Almost all do, but the ultra-compact models aren't upgrade-friendly. It doesn't really matter if you go AMD or Intel (as long as it's not Celeron). They're both excellent processors. Generally Intel will run a little cooler requiring quieter cooling, but that's not always the case. Make sure you get an absolute minimum of 512 MB RAM (the more, the better). Any other fluff is completely up to you, but having a fast hard drive may be important. Oh, and don't get XP Home Edition if you plan to do anything networking. It sucks bad. XP Pro is the only way to go (unless you go Linux).
General reliability is important, but customer support is more important. Here are the latest charts from Consumer Reports. (I don't trust Zdnet and Cnet publications for completely accurate ratings -- too commercial)
overall reliability
computer tech support
ratings of sample machines in similar performance class
So, if you truly want the most bang for your buck, you would seriously be hard-pressed to beat the Dell's, especially the crazy deals that pop up every couple weeks on the Dell deals, which
http://www.DealCatcher.com watches for closely.