No matter how it looks, or where it takes you, the end of grad school necessitates a change. You are completing one cycle and starting another, no matter if that cycle is academic, professional, personal, intellectual. As with everything, your mileage may vary, but here is a list of things I lost and found after my defense (some immediate, so much later, and I'm sure there will be more things on both lists in another year, or another decade.)
Things I lost:
A sense of myself as a student, always learning and growing
An intellectual community with tons of shared interests, vocabulary, references, and ways of thinking
A vision for the future that was standardized
A good excuse for not going to things I didn't want to go to ("sorry, can't! will be writing - big deadline!)
Good reasons to be self-deprecating ("Oh I'm just a grad student) in professional, and sometimes personal, situations
A plan for the future that was assured for semesters or years at a time
Things I gained:
A (tentative! still growing into it!) identity as an expert in my subject field, and also in my skill set
A new understanding that plans are just plans, and that being open to change and new opportunities would serve me professionally and personally (even if it's really scary to enact those things, or even think about them sometimes)
An expanded definition of the word colleague, and where I could find those people
A desire to engage in my field beyond what I could cite or what I could write
The realization that even if I were to stay an academic, that would always be a choice - and that I was free to continue to choose what I wanted to do "when I grew up" forever
Much clearer work/off boundaries
An appreciation for how hard I worked to actually write and defend a dissertation
New ways to think about, and talk about, the skills I gained researching and writing a dissertation
New confidence in my ability to communicate complex ideas in a variety of ways
The knowledge that what made grad school hard often had very little to do with the quality of my work, and much more to do with the system in which that work was produced and evaluated
More clarity around the behaviors and beliefs that I held and reinforced that made grad school hard
Learning for fun instead of to survive
A degree that certifies me as a researcher and writer and instructor at the very top of her field