Let me add another comment on flash. I don't recommend using it. Why? Well, as was said, it requires a fast connection to really work as developed usually. I don't think that the site would want to alienate people without a cable internet connection. As said, it doesn't always work with older browsers. A lot of the internet has the latest browsers, sure; but a lot don't! Those users shouldn't be alienated. Not everyone has Flash plugins. While PHP is server side, Flash is client side. That means that instead of relying on ONE computer to have the necessary support, you rely on EVERY computer to have the necessary support. So either they get Flash or they can't see something on the site. That can be aggravating, and can alienate even more users.
But one of the biggest problems I have with it is that people use Flash a lot of times to give visual appeal to their websites. Okay, that's nice ... but then they never work on the actual content -- which, if you think about it, is why the user is there in the first place!
I don't mean to go off on a usability rant here, but I think it would be a real shame if this site was designed for only a small portion of the internet. It will be important to keep in mind that some people might not be using IE6 or newest/latest browser from Microsoft with every plugin. Not everyone has a T1 line (okay, slight exageration, but I suspect many people may be going there from school ... and my school at least has notoriously slow connection speeds), so massive images or flash files, or anything requiring excesive times to load is not good. People might be acessing the webpage in a text only browser. Or even from a handheld device. They might have dissabilities (see
the W3C guidelines for this)
On website design, I think the biggest mistake is that people forget to keep things simple. Webmasters
forget that a user is there to get whatever information his site has to offer
and not to see the latest new-fangled internet wizardry available. Sure an animation might be "cool" or "neat" ... the real question is, does it somehow explain or relate information to the user better and/or more succintly than text, or some other thing.