Yes, the 4.x Netscape really is awful on Linux, and I would never ask a site to be compatible with it... but with Konqueror and Mozilla (and Netscape 6.x), things have really improved -- enough to where my laptop now runs Linux full time.
Fonts are fine -- KDE 2.2 comes with plenty, and supports anti-aliasing (no more pixellation). My only issue with VBulletin is how the tables don't line up.
I checked out the HTML source and found the problem. I don't know if it's against specification or not, I just know Konqueror and Mozilla render it differently from MSIE. The problem? Mixing Percents with pixel widths in tables. Example:
The expected effect is that the second column will fill the remaining space. The problem is, the only way to make that actually work (in my experience) is to place a transparent GIF in the 200 pixel cell, that is 200 pixels wide. That would fix the problem all together I believe.
As for the <textarea> size -- I think that VBulletin checks for MSIE, and if it doesn't find that string it assumes it's Netscape (which normally makes form fields way too large). Konqueror is similar to IE in that regard, though, so the compensation makes this text box very tall and skinny...
Ah, well, if the above things are part of a template, at least I can fix it on the sites I have some part in... or I can fix it in the PHP code, either way.
As for Opera, I don't know what their goal is, but I hope it is to simply be 100% compliant. That is what Mozilla's goal is, and if more browsers do this, IE will soon become the odd-ball.
Maybe not, but realistically if we can get standards compliance to be taken seriously, we won't see so many people locked into one platform. It doesn't take much to break away (though oddly enough, Windows 2000 crashed three times while trying to burn RedHat 7.1 CDs...)
By the way, when I mentioned that we should be standards-compliant, I was refering to browsers (ie, IE), not VBulletin itself.