Backtrack 5 R3 Gnome x86_64 and Windows 7 Professional
Backtrack 5 R3:
Completely amazing over all and is a "Hackers Paradise" in my opinion.
Linux adds more security (I probably ruin this by running as root all day, yes I know it's bad to do this)
Comes with tons hacking tools pre-installed, giving you the ability to know you are using malware free tools.
It is completely free
Always being updated and expanded on, improving at a rapid pace and staying on top of the latest security threats.
Linux is not as populated as other OS types (meaning if a hacker wants to target millions of people they will more than likely not target Linux operating systems, and would create it to affect a much more populated OS)
Customization to any file /*
Light weight and small
Supports GUI and CLI interfaces, allowing you to repair files that could be corrupted by using the CLI
Not very user friendly
Support for errors / bugs may be hard to find at times
Could easily destroy and/or manipulate important files, if you are not familiar with Linux, and are running as root.
Some files not supported, and can not be configured to run through wine
Windows 7 Professional:
Better public support for bugs / errors / issues
Better for gaming
Supports most, if not all file types
Less secure, if precautions are not met (Patches, updates, open ports, etc)
Easier target for viruses / exploits
Not light weight
Only has GUI accessibility and can not run without it
Not free to the public $$$
I think it is always nice to be dual booting, even if the other os is only going to be a 1GB partition, just so you can go grab files, research, etc in the case of a error.
For those that know