I think that because you know what it's like to have a girl, you probably feel more comfortable with another one.
I have a DD and we'll be TTC #2 soon. I'm really hoping for a boy but it would also be really nice for DD to have a sister. DH doesn't mind either way, he's smitten with his little girl so I'm sure he'd be excited to have another.
I think that because I had such a hard time when DD was a newborn, I'm scared of going through that again. So if I have a boy I kind of feel like I'll have a better chance of it all being different next time, if that makes sense.
Anyhoo, if we're lucky enough to fall pregnant again I'm sure when we discover the gender at the birth we'll be excited either way!