Variable Writting Style Preference

There are tons of different recommended ways to write variables that have two different words in them. With so many different recommendations on the casing & spacing, I usually find myself stuck in which one I want to use, or end up using all of them and looking alittle amateur. So my question is, out of the following styles for say...writting varaible with the two words, "apple" and "sauce" in it, which is most preferable to you all?

[list=1][*]datatype apple_sauce;[*]datatype appleSauce;[*]datatype AppleSauce;[*]datatype appleSAUCE;[/list=1]

I use bot apple_sauce and appleSauce depending on whatever I choose to use when I start writing a program.

Hi

I too generally use the two apple_sauce and appleSauce..............appleSauce more often.