I've thought about this when people ask me why OS X is better than windows. I start rambling about the dock, menu bar, the visual cues, lack of dialogs and pop ups, universal *same* dictionary in *every* text box (the reason I use safari over other browsers)..... The list is pretty endless.
It's at that point that I realize, again, that in order to appreciate OS X you need to *use* it. I've never found any one thing, it's all the little things that work so nicely together. In the end, a typical windows user will not really get it, and unless they put about 6 months into really using OS X, won't really understand. It took me about 6 months to get really comfortable with my powerbook, now I can't go back and my windows desktop is off most of the time.
RE: sleep mode, I have a fujitsu lifebook from work that the sleep mode has been very reliable for me, I think it's dells that have the issue with sleep, with good hardware it should work.