OS: Windows 7, 64-bit
Java: JRE 7, 64-bit
Browsers: Internet Explorer 9 and Firefox 4

The steps to reproduce:
1) Un-install all versions of Java from your system.
2) Install JRE 7 64-bit
3) Installation completes
4) Verify the newly installed Java 7 64-bit on: http://java.com/en/download/installed.jsp

Expecting behavior:
1) Installation completes successfully
2) Verifies that you have Java 7 64-bit installed

Real life behavior:
1) Installation completes successfully
2) Upon verification on: http://java.com/en/download/installed.jsp, it returns with missing plug-in error and suggests you to install Java version 6u26 or later

Also tested with Secunia's (http://www.secunia.com) Java based "scan" applet, it returnes with the following message: "There might be problems loading the Java applet in your browser. If you are sure that Java installed (version 0.6.x or later) and functional, then please press OK to proceed anyway".
The solution to this issue is to install 32bit JRE with the 32bit browsers.