SQL Developer

I have been trying to install Oracle SQL Developer, Toad, and Oracle Express on my work computer. Installing SQL Developer and Toad was pretty straightforward, and I was able to browse the XE database with SQL Developer. But after installing Toad, problems started. Toad was using Oracle XE's registry settings to locate ORACLE_HOME and oci.dll. So I tried changing the settings for Oracle XE in the registry. Toad now works, but not Oracle XE. And while I was going through this all, I even had a time when I had Toad and oracle xe working, but not SQL Developer. It almost looks like you can choose two of the products, but not all three.

So, my question to the community at large is "Can it be done?". In what directories do you have each product installed? What environment variables do you have set? Where is your tnsnames.ora? What Oracle registry settings do you have set (namely HKLM\SOFTWARE\Wow6432Node\ORACLE\KEY_XE)?

I can post my current settings, but I've been through so many iterations that these current settings don't really matter that much.

Here are the details I am looking for
Path to sqldeveloper.exe
Path to oracle.exe (for Oracle XE)

Environment Variables
ORACLE_HOME
ORACLE_BASE
TNS_ADMIN
PATH (just the oracle stuff)

Registry Settings
HKLM\SOFTWARE\Wow6432Node\ORACLE\KEY_XE\ORACLE_HOME
HKLM\SOFTWARE\Wow6432Node\ORACLE\KEY_XE\ORACLE_BASE
HKLM\SOFTWARE\Wow6432Node\ORACLE\KEY_XE\TNS_ADMIN
HKLM\SOFTWARE\Wow6432Node\ORACLE\KEY_XE\OLEDB
HKLM\SOFTWARE\Wow6432Node\ORACLE\KEY_XE\ORAMTS_CP_TRACE_DIR