If you want to use Linux as your desktop OS however want to keep using Toad, thanks to Wine it is possible. I've succeed running Toad 10.5 on 64-bit Ubuntu 12.10.

These are steps to install Toad:

1. Install Wine

$ sudo add-apt-repository ppa:ubuntu-wine/ppa
$ sudo apt-get update
$ sudo apt-get install wine1.4

2. Configure Wine as 32-bit. Since you are running a 64-bit OS, Wine runs 64-bit basis as well. However Toad is a 32-bit application that requires 32-bit Oracle client. Therefore you need configure Wine to run on 32-bit basis.

$ rm -rf ~/.wine*
$ WINEPREFIX='/home/<user_name>/prefix32' WINEARCH='win32' wine 'wineboot'

3. Install requirements. I recommend installing .Net Framework first because it's a bit problematic and takes the longest time. During its setup, you will be asked to download different versions and place into Winetricks's cache directory. So you will need to run the command several times.

$ winetricks dotnet35sp1

After successfully completing previous step, install rest of the requirements.

$ winetricks gecko fontfix gdiplus msxml3 msxml4 msxml6 vcrun2005sp1 vcrun2008 winxp volnumcd 

4. Install Oracle Client. Copy installation files of Oracle Client for 32-bit Windows into ~/.wine/drive_c/tmp. Unzip the installation and run setup. During setup, choose "Runtime" option and ignore any prerequisite check failures.

$ wine "c:\tmp\client\setup.exe"

Do not forget to copy your tnsnames.ora file to ~/.wine/drive_c/app/<user_name>/product/11.2.0/client_1/network/admin after setup.

5. Install Toad. You might copy setup file again into ~/.wine/drive_c/tmp as well. To run setup:

$ wine "c:\tmp\toad.exe"

6. Run Toad. Installation creates desktop shortcuts, so it's possible to run Toad from these shortcuts or directly through Wine:

$ wine "C:\Program Files\Quest Software\Toad for Oracle 10.5\Toad.exe" 
or
$ wine ~/.wine/drive_c/Program\ Files/Quest\ Software/Toad\ for\ Oracle\ 10.5/Toad.exe

Enjoy Linux