Designing a website that "looks good" AND works effectively is far more complex than most users seem to realise; you have to take into account that there are hundreds of browser versions in use, many different platforms, user preferences that vary greatly and over which you have no control, different window sizes, varying connection speeds... the list goes on.

But I find the best two ways to approach this are either to do what you have done, and create multiple versions of the site and allow the user to choose which version they would like to see, or, to use a buzzword, let the pages "degrade gracefully" - take advantage of the latest technologies that the most recent versions of browsers feature, but don't use them to carry the crucial message or functionality of the site. This way the site is fully functional to those using text-only or older versions of browsers, but gives those using the most up-to-date browsers that little extra, kind of like icing on a good-tasting cake.

Good web design is not about using snazzy bells-and-whistles; it is about making sure that the site's architecture works and allows people to get to the content or whatever they are there to view, and makes this information accessible to everyone.

Bear in mind that it is better to have people complaining about the asthetics of the site than having people complain about not being able to reach it at all.

John Allsopp has written a thoughtful essay which deals with the issue: The Dao of Web Design. It's a rather interesting read and gives advice about how web designers should approach the problem.

I hope this helps.