Not necessarily. I sealed off the fan vents in the bottom of my case as well as the side panel, forcing all of the air to flow in one direction with nice positive pressure.
The 700/800D just about call for water-cooling or modding in order to get the best out of them.
Have you looked at the Silverstone FT02 (the revised version with the AP181 fans)?
If you need more space the upcoming TJ11 should be amazing.
Of course, it will almost certainly come in at ~$300-350. Here are some more photos of the prototype. It's rough because it's unfinished and there is plastic/steel in place of aluminum on the retail version.
TJ11 56k Warning
http://forums.techpowerup.com/showthread.php?t=123722
For half that price, or about $155, you should take a good look at the Fractal Design Define XL. Clean styling, spacious, nice features, and lots of modding potential. If shipping from Canada (NCIX) weren't so high, I'd likely own at least one of Fractal's cases by now.
http://www.youtube.com/watch?v=nUZbDiwXYJo
http://www.fractal-design.com/?view=product&category=2&prod=54