Aos4 is not only numerically greater than Aos 3 ;-) But is the natural successor to Aos3 and comes bundled with the all features you probably will know about already.
Surfing the net is vital these days; nothing pre-Aos4 is suitable for internet browsing - sorry iBrowse advocates - but its no longer 1993.
And contrary to what HaywirePC posted above; Aos4 does in fact come ready bundled or as you put it pre-configured (probably wrong word you picked there) with all the apps and utilities that you would expect. Quick examples, DOpus, File, Simplemail/Yam, SGrab, AmiFTP, Pftp and many other popular apps you will find on OSDepot. They where already installed on the hard drive when my SAM 460 arrived - they are also available on the included CD.
Personally I'd love talk about this again say end of July when perhaps someone can compare Timberwolf running on AmigaOS Classic vs AmigaOS 2011. That would be quite something to see running on an ancient A4000!
Edit: drHirudo - Yeah good points. Aos3 isn't for modern computing. Hence why its referred to as Classic, by just about everyone.
Edit 2: Gulliver - Of course I have no idea where you come from as your Avatar says nothing. But I would imagine other countries (if they haven't already) will be joining the UK and ditching all TV analogue broadcasts. "And they call it progress!"