They probably make up the majority of your customer base. Techie types tend to look down on the uninitiated. Make sure you or your techies aren't guilty of this. AOL in particular is a force to reckon with. I personally optimize my web layouts for 800x600.
Most pro sites do also.
I use Mac equipment but also am keenly aware that most people don't. The Macs make text and graphics smaller and lighter than they appear on PC's. The point is, take time to view your site on multiple machines and monitor sizes. Even with vision correction, VERY small text is difficult to read, and any color against black is a nightmare. While it looks cool, it isn't the best combination for extensive reading.