Okay, well if you have to know my opinion on the best FE then that would be GameEx.
1. Be easy to configure with multiple emulators namely the ones mentioned in my initial message
I have just finished writing the GameEx Setup Wizard. And it is about to be released shortly. It guides you through the process of setting everything up and makes things as easy as possible. I'm currently in review stage with Tom who is the author of GameEx, so it's only a matter of time before it gets released. So it's in my humble opinion that you wait for that release and check out GameEx with the new Setup Wizard. Meanwhile check out some other FE's to see how it compares.
2. Be able to play game previews/ game images and marquees
Yes, most FE's can do this and so can GameEx. It's got a large feature list, check out the official website for more info.
3. Look clean and profesional and have customisable menu's/ backgrounds (animated if possible)
The one thing that will strike you first up about GameEx is it's stability and professional quality. It could very well be a commercial product, although it does have a nag screen at the start to encourage donations it's still free. With all the work in coding and maintaining the support websites and everything it's worth it I believe, but there is no obligation. GameEx is almost always updated weekly. It is highly actively in development and features are being added all the time. You can make a request on the forum and I guarentee that if it's a good idea it will be implemented. So thats a big plus too.
It's also very customisable and thanks to the GameEx Theme Editor you can easily edit the layouts and images in a Theme. It also supports AVI video playback in the background.
4. Easy to navigate with arcade controls
Yes, all the arcade controls are supported.
Another cool thing about GameEx, apart from it's huge feature list and quality, is that there is a really great community that supports it. Check out the forums on the official GameEx site if you ever need any help and you will always get a reply from someone willing to help.
What more can I say, the proof of the pudding is in the eating...
http://www.tomspeirs.com/gameex/