There are many factors that affect quality:

1. The broadcasting setup and technology.

2. The broadcasting bandwidth.

3. Internet bandwidth available (or lack of congestion.)

4. Your ISP.

5. Your connection to the internet.  (<-- GREATEST FACTOR!)

6. Your computer (CPU, hard drive, etc,...)  (<-- Old computers might not perform well.)

7. Your sound card.  (<-- TRY NAME BRAND)

8. Your speakers.  (<-- ANOTHER GREAT FACTOR!) 

1. BROADCASTING SETUP AND TECHNOLOGY.  You cannot do anything about this.  Each broadcaster decides how much they want to invest on broadcasting, and will go so far to acquire expertise in achieving the best quality.  If they are cheap, it probably isn't their fault.  They simply don't value their internet broadcasts beyond a limited dedicated audience.  For some broadcasters, this makes sense.  For you, however, unless you are a dedicated listener, you probably won't be interested in such stations.  Most of these stations already broadcast locally in their area, and consider the internet a nice addition, but not truly necessary.  They primarily serve their local airwave listeners.  This is not to say you won't find good quality "local" stations, but simply that few of them have an incentive to invest in expensive broadcasting technology for the internet.  The best stations are those who serve the internet only, as it is imperative that they impress this audience, their only audience!

2. BROADCASTING BANDWIDTH. This is just an extension of #1.  However, this sets a specific limit to how many kilobits per second they are willing to transmit (e.g., 32k).  This means that no matter how fast your connection is, you won't get any better than this.  As you will see, if you have a 56k modem that connects between 33k and 50k, then you should be able to achieve the maximum speed for many stations.  However, high bandwidth broadcasters (64k+) will require a downgrade for you to hear them via a regular modem.  If you want to enjoy their highest available quality, then you might want to consider #5, your connection to the internet.

3. INTERNET BANDWIDTH AVAILABLE.  Basically, this means that between 7pm and 11pm, look out for rush hour traffic.  This is also out of your control, although having a high speed dedicated connection to the internet seems to reduce the problem quite a bit.  My suspicion is that the internet and ISPs always give low priority to modem users, but I can be paranoid at times.  

4. YOUR ISP.  These are the ones you pay every month for internet access, unless you are a student, in which case your school is probably your ISP.  They differ greatly in terms of quality.  They also change every day, so I don't bother to try to rate them.  Also, there's a world of difference between 56k modems, ISDN, DSL and Cable modems!  With technology growing so fast, today's ratings are out-of-date tomorrow.  Pray!

 5. YOUR CONNECTION TO THE INTERNET.  This affects your ability to use #2, the broadcasting bandwidth, to capacity.  If you are not getting a broadcasters maximum speed, it is probably because your connection cannot support it.  If you are using a 56k modem, forget the 56k part, and try to find out what speed you are really connecting at.  If it says you connected at 33,000 bps, then you only got 32-33k, not 56k!  It could be your modem or your phone line limiting your speed, but it is probably your ISP.  Give them a call if you are getting less than 40k and ask if there is anything they can do.  Try others if it is not too difficult. As a technologist, I recommend you do not use AOL!  I refuse to help people who have it because it uses proprietary technology to connect to the internet.  Therefore, it doesn't work with a lot of internet software that is based on open standards.  In the technology world, proprietary is bad, open standards are good.  

If you can afford it, consider a higher speed alternative such as DSL or a cable modem.  They both tend to offer at least 160k, topping even the highest quality audio broadcasts!  DSL is better, but Cable is cheaper.  Cable will run you around $40/month, if it is available in your area.  Check with your cable company.  Bay Village, Ohio has it!  DSL starts at $50/month, which gives more than enough speed for the average user.  If this seems pricey, keep in mind that you can get rid of the $20/month ISP you are currently paying for; and, if you have an extra phone line for the internet, you can get rid of that too.  DSL does not tie up your regular voice phone line!  

DSL is not technically feasible for everyone.  Using your phone number and address, a DSL ISP will see if you are close enough to the phone company's switching office to get it.  I was told that I am 1.9 miles from one, more than close enough.  

Another great thing about high speed access is that it is easy to share it among connected computers, and you can probably listen to the radio while you surf.  If you have a modem, you might have to make a choice at any given moment between internet radio and web browsing, as the radio might not leave much bandwidth for browsing.  IF you choose DSL or a cable modem, then add to the benefits the time you will save dodging the "world wide wait!"

Joshua Branch will help Clevelanders get DSL and other high speed solutions soon, so check here again for help.  

6.  YOUR COMPUTER.  I'm not going to get into technical details here, but if it's old, it might be a problem.  Just try it out.  Internet radio doesn't really use much of your resources.  If you have problems, remember that new computers are cheap, and you can get a good internet tool for under $1000.  Avoid 3 year ISP commitments, though ($400 rebates!)  They limit you to 56k modems.  Read #5 to remind yourself why 56k modems are going out-of-date for today's internet usage.  They know it, and they want to trap you.

7.  YOUR SOUND CARD.  If you already have one, then try it out.  Most should work; but, if it isn't name brand (Yamaha, SoundBlaster, etc,...) then it is a risk, so be careful when buying a new one.  

8.  YOUR SPEAKERS.  If you are like me, you bought cheap ones because second best just wouldn't do.  These days you can get full surround sound for your computer, although that is perhaps overkill if you aren't going to watch movies on a DVD player. 

I have a solution for you music enthusiasts who love your stereo, and don't understand why internet radio broadcasts don't come out of it.  For $70, you can get a 2.4 gigahertz audio/video transmitter that will bring internet audio to life at X10.COM.  They call it MP3 Anywhere!  I love it and am really happy.  Come over my house, and you would never know it wasn't a regular FM station!  With DSL, I can listen all day, while surfing, or talking on the phone!  In fact, I am jamming OnePlace.com right now!