There are many motivating reasons for improving your home. Most of the time it's because you'll enjoy the results, but often it's also because you want your home to be more attractive to future homebuyers.
As you consider different projects to tackle you might want to check out Remodeling Magazine's Cost vs. Value report. (www.CostVsValue.com)
It's an amazing amount of information that you can sort through by geographical region. Unfortunately, they don't feature a section on Nashville, but you can view information on Knoxville and Memphis and get an idea of what the numbers would be here in Middle Tennessee.
For a "midrange" home, adding an attic bedroom was the top choice, preserving 90% of it's value at resale. This means if you spend $10,000 to do the project, you'd make an addition $9,000 when you sell the home.
For a "high-end" home, adding or renovating a bathroom was at the top of the list, preserving around 60% of it's value.