For those interested,
On Line 178, Find:
Where ## = a number greater than 75, and to a maximum of 100.
Please note, while this will increase the default quality of thumbnails, the file sizes will be bigger. However, for anyone that cares about quality images on their blogs, you won't mind the trade-off. The default quality of the generated thumbs, on a hi-res monitor, are just atrocious. At least this gives you a chance to have presentable thumbnails. Use at your own risk, and make a backup of the original before editing core files.
An Ideal Solution
What would be an ideal solution is to let users choose if they'd like to use imagemagick or the default options. This would let users with imagemagick installed on their servers to specify the switches to apply sharpness, radius, contrast, etc on a single default variable string, as an Admin Option. This would produce superior thumbs, and, more importantly, give WP users a choice. But at the very least, allow users to specify a quality variable on the default options. 75 is simply inadequate to produce acceptable quality thumbnails.
Please Also Note
Please do not suggest I use a plugin to address the quality issue. I'm interested in WordPress improving THEIR inherent image quality routines/options rather than forcing people to rely on plugins to address a [lack of] quality issue that they include as a default.