ThinkPad G series
This category is not about the Lenovo G series, which is part of the Lenovo 3000 Value Line.
The G series was developed as a very configurable budget machine line in mind, allowing for a wide variety of configurations that could be either slow and cheap, or fast and expensive. To achieve this, the G series used the desktop Pentium 4 line, as they were mostly much cheaper than their mobile Pentium 4 equivalent. However, the disadvantage of the desktop Pentium 4 line had to be accounted for in its design. This would result in a machine that was very thick and heavy, due to the cooling requirements needed by the desktop Pentium 4.
The G series eventually used Intel's mobile offerings, which gave them slightly better battery life. Unfortunately, it was not enough to keep the G series from being discontinued afterwards, due to the unattractive weight and size.
The G series was also the last ThinkPad line-up to feature a floppy drive, an optical drive, and a hard drive altogether in one package.