I'm still only halfway there (name change and gender marker <1month away!) but I can only imagine the feeling is similar to after graduating.
I graduated highschool, and thought I'd be done with boring school, college would be like Animal House. Well, it was like Animal House, but it still was a lot of boring schoolwork and homework.
I graduated college and thought I'd find a job that made me happy and made for easy livin'. NOPE! More being broke (technically more broke with loans) and working lame jobs...
So, after those "great achievements" I just did what I do any other day: try to capitalize on opportunities, avoid risks, and have a good time.
Since then, I've paid off my loans, traveled the world, bought a house and had many deeply meaningful relationships. I'm now doing service work for very very little money, and it feels great! My family, friends, and neighbors (the good ones) are what I live for. My sister has a 5 month baby boy, and I can't wait to smother him with love, as well as help out by doing some free babysitting.
I am still transitioning, slowly ($), but it's ok. I feel like I've got transition on the back burner. Perhaps I already understand that finally getting "the surgery," while it will be a very awesome thing, is just a small detail in my life.
When I'm finished transitioning, if I haven't already, I would like to address a few other things about me:
I don't dance enough (too self-conscious)
I've stopped creating art and music
I don't give enough of myself/ I need to do more
More exercise
More traveling!
I need to make my lifestyle more sustainable (sorta contradicts with traveling

)
I've got my list ready to go

Besides "problems" that I want to tackle in this life, I also have many different hobbies, or things that make me happy that I can do. Like teaching, or making art or music, I can do these all day, everyday, and share it with others... and it makes me happy!
I think the ultimate thing in my life will be adopting a child. I have long had a feeling that I would like to adopt and raise a child. Being a parent is a lifelong thing and a rewarding experience. It is probably the most effective way that I can make this world a better place.