Okay being that this is a voice over demo reel and as such will be your calling card, you want it to sound as polished and professional as it can be. So from what you have said in your posts I gather you do not have the experience or equipment to record professional voice overs yourself. So my suggestion would be to spend some money for an hour or so at a top notch studio in your area and record your demo there. Make sure you go to a studio that does VO on a regular basis.
The G-Raids are great drives but they will not solve your problem of having to move drives from station to station. You will need to look into the Xserve Raid and Xsan as Shane suggested.
What mic are you using?
Are you going into a mixer or pre amp or are you plugged straight into the mic in jack of your computer?
The warm, resonant sound you hear in professional voice over is usually a combination of the voice, the mic and the pre amp. Some compression and a subtle reverb may be added.