I've recently come across a very useful program with regards to addressing a problem likely everyone has run into (whether they realized it or not) at some point in their use of the Internet. Steve Gibson at GRC has recently released a very well written tool for benchmarking DNS.
This tool will analyze your system's existing DNS setup and then recommend steps that you can take to improve DNS performance. At that point, it will give you the option to create your own custom "Top 50 Resolvers" list so you can use the DNS servers that work best for you (since the performance of DNS is inherently relative to your current location - what works for someone else may not work for you). You can find the program and instructions on how to use it at the link below. The tool is very lightweight (only 163KB), and best of all... it's completely free.
For more information on how the DNS Benchmark tool works and what everything in the interface actually means, read over Steve's documentation of the program. It looks complicated, but once you read through and know what everything means, it's a very powerful program that displays a lot of information in a very simplified manner.
Another tool from Steve I have also come across is his DNS Spoofability Test. Once you have used the Benchmark tool above to determine which DNS servers are the fastest at your location, configure your computer to use them, and then run the Spoofability Test. If you want further details on the nature of the issue, you can read the webpage at the link below. At the top of the page, Steve provides the background on the problem, describes the problem itself in a bit more detail, and finally, provides a link to his Spoofability Test tool at the bottom.