Noncommittal
I'm torn. You say you are going to write a novel for NaNoWriMo (major kudos, by the way; it's a goal of mine too one day), you have so many ideas, you can't decide, but you want me to write about my favorite genre? I would much rather tailor advice to you based on your ideas and desires, my favorite genre be damned.
Why do you write? To bring something into existence? To challenge yourself? To let your soul sing?
What excites you? If you had to write ten thousand words about anything, right now, due before midnight, what could keep you so engaged that you didn't even notice your coffee went cold...two hours ago?
Do you have stories and characters scraping and clawing and rattling around in your head? Those are the manifestations of your creativity and individuality. You are doing the world a disservice by keeping them locked in their padded cells. They are but passengers stowed away on the vessel that is You. Will you let them sink to Davy Jones' Locker or grant them the immortality they deserve?
Spend an hour and write down every idea you have. Every. Single. One. Take two if you need it. Characters, ideas, scenes, time periods, dialog, descriptions, histories, etc. Write them all. They can be as high level as "a time-traveling sci-fi story about dinosaurs in space" or as low level as "Timmy opens the closet and finds pink wrapping paper for his mom's Valentine's Day gift. Instead of grabbing the pink roll, he grabs the baby blue one. The one with Spider-Man and snowflakes and the words 'Merry Christmas' emblazened in white. The one he happily ripped to shreds to uncover a beloved Lego set nearly two months ago. His jaw drops in disbelief as he connects the dots, and the magic is lost, forever." Then pick your favorites from that list and spend a half hour or so fleshing each one out. Some of them will die on the vine. Others will bear unforseen bounties. Put all of those elements into a story. All of the good ones. And then write and write and keep writing until the story is done.
Let your story pick its genre.
As for my favorite genre? Much like this non-answer answer to your challenge, I love the genre-buster.
Best of luck in November. Feel free to challenge us again if you get stuck. :-)