Hi elian, hi list!
One search field + button, a wikipedia logo and below the different language wikipedias ("La encyclopedie libre française (5000
articles)",
"Die deutsche freie Enzyklopädie (5800 Artikel)" and so on)
People don't like to read too much on a front page. They prefer a
simple
and fast-loading interface - then they will stay.
I also don't see much gain in flags, maps, or any other kind of images. We have 25 Wikipedia language subprojects (or whatever they should be called, now that things are growing together), so you can find the one you want easily when you skim over the page.
Kurt