You can use Audacity, but just as you point out that you need a skilled and accomplished singer, sound engineering is not just a matter of pressing a button. Making good recordings takes time and experience.
When I say that you need expensive equipment, the studio in which that vocal was recorded would probably use a microphone something like this:
http://www.gear4music.com/Neumann_U87_A ... L_AyDfv5AR
The microphone would be initially amplified with a pre amp such as this:
http://www.millennium-music.co.uk/home/ ... ode=detail
They would probably use a mixing desk something like this:
http://www.kmraudio.com/catalogue/produ ... ts_id=1994
and would then use a rack load of outboard effects (often hardware effects, but may also use software effects).
There would be engineers, producers, technicians etc. all experienced professionals with years of experience in recording. Even the room that the recording is done in will have been designed and acoustically treated to create a "perfect" recording environment.
So we are left trying to produce high quality recordings on a relatively tiny budget. Fortunately Audacity is free, allowing us to use our limited funds on hardware such as a nice microphone, a decent soundcard, some studio monitors etc.
Audacity is a great piece of software, and capable of excellent results. With the addition of LADSPA effects we can use reverb, compression, limiting, ADT, and lots more, but using them well takes time and experience.
When I first started recording, I had an old 1/4" tape machine and a Sure SM58 microphone. The first recordings were not great, but I recorded some music, and gradually the recordings improved. Eventually I reached a point where the equipment was the limiting factor, and I had to upgrade, but by this time I knew much more about recording than when I started.
I think that sometimes too much emphasis gets put on equipment. While it is true that bad equipment will not produce great results, expensive equipment will not either unless you know how to use it. The important thing is to get started and do some recording. Audacity will not be the component of your recording system that limits your creativity.
