They are both wonderful, but different!!
My all-time favorite cats have been female. They tend to be a little more possessive, and picky about who they love. My 2 favorite cats (girls) would not let anyone but me pet them. They weren't scared of others, they just didn't have any interest in them. I stil have one of them, and she lays on me every night and bathes my face when I sleep. She's so sweet!!
However, the biggest "babies" I have ever had have been my male kitties. They are cuddly, calm (after about 3 yrs old) and super sweet to everyone!! I had one that used to curl up around my neck (when I was sitting up) to sleep, one that used to sleep under the covers with his head on my pillow, one that used to jump in the car everywhere we went, and two that regularly had "sleepovers" at my neighbor's houses.
I do think boys tend to be cuddlier, and funnier than girls. Girl kitties tend to be more serious. Right now, I have 3 girls and 3 boys. My girls NEVER come out to see strangers, but 2 of my 3 boys come to greet any guests who come into my home. One of my boys is an indoor/outdoor cat, and he regularly brings lizards, snakes and mice into my home

. I generally want to kill him, but he is just so funny that I cannot!!
A year ago, my dd had to have surgery and she was FREAKING out about it. So, to take her mind off the surgery, dh and I went to pick out a kitten to surprise her. We got her the cuddliest little boy we could find. He ADORES her, and she adores him. I don't think she would've had nearly as much fun with a girl.
If you get boys neutered early enough (at 6 months), you will never have a spaying problem. We also de-claw our kitties, and the earlier you can do that (if you are going to do it), the easier it is on them.
Both genders are awesome...it just depends on what type of personality you are looking for.