Graphics
Huh? Graphics fall under "fun extras"? As far as I'm concerned, yeah. You can have a completely functional, and pretty darn attractive, page with absolutely no graphics. It requires a bit of creativity regarding font types and colors and such, but it's not all that hard. Because I didn't have a way to create graphics for a long time, rengawm.com is actually the first site I've made that employed graphics in the layout. Now, granted, your site won't be incredibly glamorous without graphics, but it gets the job done.

However, should you find yourself in possession of a decent quality graphical editor, such as Photoshop, a few hours of "creativity extraction" can produce an elegant and sophisticated graphical interface for your site. I'm not claiming that mine is either elegant or sophisticated, because graphical creativity is something I don't have in abundant supply. But it looks much better than it would with square table cells instead of rounded, "3-D" tabs.

Graphics, when used properly, are a powerful tool. But "with great power comes great responsibility." I've seen way too many sites with random pictures, ugly GIF animations, and just plain strange graphical backgrounds. If you're going to use graphics, PLEASE don't go crazy with them. I don't want to see every single funny bouncing image you've dug up from a clip art collection, and I don't think a lot of other people would either.

JavaScript
This is another one of the nice touches you can add. It's what makes my tabs turn black and get more shadowy when you move the mouse over them. It can do a lot more than that too, but my experience with it is fairly limited. I think all links or buttons should have some sort of indication when you move the mouse over them that it'll take you somewhere. Not much is more confusing than links hidden in a paragraph that are just one color tone away from the rest of the text. I'm not going to squint at my cursor to see if it turns into a little hand, I want obvious indication that I'm about to click on something that will take me to another page.

CSS can make raw text links change color, become bold, get an underline, or border... and JavaScript can take care of the pictures. Flash can do the same, I'm sure, but I don't like loading times, and I know nothing about flash... not to mention that it's free (and moderately easy) to make JavaScript code. For tutorials, I will once again point to PageResource.com's JavaScript Tutorials.