"Your recording is only as good as the weakest link in your recording chain" - Tommy Griffiths, Voices.com
I found a great deal on a Rode NT1-A microphone from a fellow who was selling the contents of his studio. I am so happy with it. It is an incredibly quiet microphone, and very sensitive.
I had a few glitches with distortion when monitoring while setting up my sound card and software, but once that was resolved, the upgrade was noticeable night and day. I'm using it with the Focusrite interface I bought last summer and in the process of setting this up, learned that one of the USB ports in my Mac is starting to malfunction.
My next goal is improve the treatment of my recording space again. Switching to an XLR mic resolved the latency issues I was struggling with when monitoring, which is great, but I am noticing again deficiencies in my space, because I live in an apartment, and there is always the trouble of random environmental noise that I can't control (other people, their children, and their pets being repeat offenders). My ultimate goal is a booth like a WhisperRoom, and a Neumann microphone, so that I could record audiobooks from home. In the meantime, I would like to upgrade from the blanket fort booth to a foam treated space. Stay tuned!
While you wait, check out this video I found by Tommy Griffiths at Voices.com addressing common problems with audition sound quality. I found it very helpful!