If you're planning a career on making music, burning it to CDs and selling them, you're planning to make money, and therefore you can afford to have a workstation dedicated to recording the music - including the programs you need (selected by quality and need, not platform) and the operating system they run on. If that means expensive programs and Windows, you want to take it, because you want it to be good - the other option is to hunt for possibly nonexistent freeware apps, and play around with them. Note that specialized software doesn't always exist on Linux, and that those apps you find (like those you mentioned) are usually made for only one (or two) main operating systems (in this case Windows, maybe Mac OS X) and the work put into them hopefully makes them good enough for the price. If you want quality, you are going to have to pay for it - open source doesn't change that.
PC studio doesn't sound too professional for me, so maybe you could get away with Linux, but if you want the best there is for PC, then I guess it's the software made by professional companies who know what they're doing. Reviews and user comments about the software should help you see if it's good for the price or not - and if it is good, you will happily pay for it. There is no such commercial way of doing things where you don't pay anything but do get (a lot of) money - if you want to make money, at first you do have to pay to get started.
Having said that, remember that sound is "merely" mechanical waves caused by pressure changes, and therefore the quality is mostly up to the hardware that creates those waves - the sound hardware, recording hardware and playing hardware. Between them the sound is usually stored in some way, nowadays oftenmost digitally. When it's digital it doesn't matter if it's open source or not, the main thing is you don't want to compress the audio to lose quality. So before anything else, if you want professional products, you need professional hardware -- cheap mics, speakers and sound cards might not do their job and handle the sound as well as those that are expensive, but made better. Software should basically know how to deal with the digital sound so that it doesn't lose quality (compress), but beyond that it's about how easy the software is to use (or how easily you learn to use it), and what kinds of tricks you can do with the digital source (sound). Now if a lot of people work on that kind of problems, the solution might be good -- but if there are not enough interested open source enthusiasts, the solution either doesn't exist, or is not as good as it could be. Commercial companies pay for their employees to make the product good, because that's what they're paid for. Therefore you can expect to get (but not necessarily know to get) better software if there are a lot of people and working hours behind it (but it is also possible that it's all wasted, and the result is bad).
Shortly said, if you want to make it good, don't spare in the wrong places. The tools don't make your music any better than it is before them, but they can make it worse, so don't spare there.