There are plenty of relatively simple Go sites like ours (
http://gogameguru.com/) that I would hope are not ugly or old-fashioned looking. I'm happy to be corrected if you disagree on this.
There are also several established, slightly older, sites (for example
http://gobase.org and
http://senseis.xmp.net) which stand out for the quality of their content. I'd really never thought about how old they were because it wasn't important to me.
In my opinion, content trumps everything else, as long as the site creator has thought about usability. On that note, if you have any usability issues with Go Game Guru, or you don't like the design (or if you do), We'd be glad to hear from you. We already got some great feedback from kirkmc, daal, hyperpape and mohsart in the early days of the site
in this thread. Most of their suggestions were implemented.
Another thing that occurred to me while writing this is that 'modern' sites don't necessarily have more bells and whistles. Just look at
kirkmc's site for a good example of a clean and minimalistic design. A nice contrast to the animated gifs of the 1990's

.
David