I always sang "good night ladies" to my son, changing the word "ladies" to his name. Then I'd make up new verses ("sweet dreams…." 3 times followed by "It's time to go to sleep". Then I'd add a few verses about what we did that day, just squeezing in the words to fit to the tune. ("We had a good day, we went to the playground, we ate some lunch, and now it's time for sleep.") It doesn't have to make sense - it just has to be calming and reassuring, surrounding him with the love you feel and the good parts of the day (especially the simple things he did as part of everyday life). I got slower and slower, quieter and quieter as we got to the end of the song, and I ended with "Mommy loves you, Daddy loves you, Nana loves you, and the puppy loves you too" (fill in any names you want of course) and then repeat of "Good night… it's time to go to sleep." After that, there was no talking, just a kiss and then I'd leave. My husband did the same thing so it was a nice tradition.
You are my Sunshine is another good one because you can slow it down and make it soothing.
I'd rethink the definition of what's "girly" and what's "boy like" and make sure that your little guy gets just as much music and cuddling. I think most classic lullabies are pretty flawed anyway, so we substituted our own.
I didn't do any finger play songs (like "Wheels on the Bus") at night because kids get too riled up. I don't do too much where they even have to sing along - it's more listening and calming down.