Text Based or Graphical Based - Will you need a site designed that is more of a text based, graphical based, or a good mix between the two?
This really despends on what your target audience is. Just 5 years ago you had to worry about how large images, flash and videos were because of dial-up users. With DSL now being the low end standard used by web designers, this isn't as much of an issue.
But if you are publishing information, studies, reports on the government (grin), then you really don't need to be talked into a high end graphic based design. A simple set of graphics will suffice. A clean look and feel is all that is needed.
If your selling something on the web, then your products will definitely be what drives the site's graphics. Flash elements is also a possibility here. Something to spice up your site that will be pleasing, but not overbearing to the users.
But sometimes you just want to go wild with graphics and flash. There is never anything wrong with doing that IF your target audience is pulled in, and not driven away from the site taking so long to load. Gamers are likely to have faster connections to the web. So building a site with high end graphics and flash will fit the target audience, and draw them in.
Site Navigation - When deciding on where to place your navigation, keep a few things in mind.
If you go with a horizonal layout, you will need to take into consideration on how long the names of your naviagtion links are. If you have too many links, it would make sense in going with a vertical layout.
Will you need dynamic drop-down menus (mouse over links on site). This is by far the best way to build your site if you have too many links for a horizontal layout, and don't want to update every page when you add a new link with a vertical layout. It also gives you the flexibility to keep building new pages, and make one simple update to the menu system.