There is little in the digital recording field that gives rise to more emotions than software. The software you choose is critically important to accomplishing your particular goals. You will need to ascertain what your needs are and find a fit from the many programs that are out there.
Suffice it to say, there are many options available - - each of which someone will have a strong opinion on. Some of the commercial industry leaders are Samplitude 2496 by Sek'd, Soundforge by Sonic Foundry, Cakewalk Pro by Cakewalk, and Cool Edit Pro by Syntrillium, among others.
Fortunately, most of these programs have demo versions available for downloading off the Web. This is a good way to check them out before laying out big bucks. Be aware though that most demo versions have limitations put on them that are removed only when you pay for the registration.
In addition, there are several very good shareware programs available. For example, I use N-Track Studio, a shareware product from www.n-track.com. It is very powerful, stable, intuitive and costs $35.00/$50.00. There are many others available from Download.com. You should also try to find them at Hitsquad.com. It is possible that one of these will meet your needs. Trying them all out is a good idea.
Some important things to look for in selecting the software are the features, resource consumption, what bit/sample rates does it support, sound quality, and, of course, price. For instance, how many tracks do you intend to record and/or playback simultaneously? Will want or need to record at 24-bit/96kHz sample rate? What is your end-market? Do you really need top-of-the-line, state-of-the-art software when all you are doing is recording a simple demo cd?
The point is that your particular needs may not be met by some software or the software may be overkill for what you want to do. Again, do your research, download some demo versions, consult your music pro. Most importantly, you should experiment with each type. See how it feels to you, whether you think like the software author thinks when it comes to problem solving. Nothing will slow down a project quicker than having to always consult the manual or to reboot when you make a mistake. To be effective, you must be comfortable with the software.