I'm a programmer, and have a solid understanding of XHTML, and back-end programming, but I have the design ability of a warthog (a particularly untalented warthog at that).
Has anyone created some open source CSS that I can drop into some well-written XHTML that will make my site look reasonably decent, without a bunch of design work?
Look at some of the CSS Frameworks. I've used ones such as Blueprint and 960. Or if you want a HTML5 CSS3 one try 52 Framework. Each of these CSS Frameworks have some ready made templates that you can just drop your content into without worrying about design. Also they have been thoroughly tested and work in all browsers, even back as far as IE6. So you can quickly build your site without worrying about any browswer issues.
If you need something more complete(there's a possible terminology mismatch here; see my comment on original question) you might try Open Source Templates. They've got a bunch of decent-looking styles that are generic enough you can easily adapt them to whatever your actual site is about.
Maybe not exactly what you are looking for, but Toucan CSS reset set's a default template that is cross-browser compatible...
Baseline is a good starting point.
