I have a new tool of choice when it comes to optimizing images for web. It is called "Imagine" and it's Open Source, fast, and awesome. Take for example the cover image I used for this post. The original version of that image was around 1 megabyte. After I ran it through Imagine, it's now down to around 299 kilobytes.
Another cool thing about Imagine is that you can drag images into it and convert them in batch. It does a great job of compressing the image more to where you can barely notice a degrade in quality. The end goal is for me to decrease the amount of load time for this website.