I don't spend a lot of time messing with my camera equipment. But it's good stuff and I couldn't get by very well with my older SLR. Currently I'm using a Canon 5D Mark II, and if you follow that link you'll see how it fared during extensive testing by the skeptics. I also shoot with L-series lenses.
All those things really mean in layman terms is that your pictures are sharper and clearer. And if you wanted to, you could blow them up to the size of billboad pictures.
And speaking of prints, there's some exciting news coming soon regarding that topic.