Well it's up to you all really.
Your personality almost does play a role in it, more than I thought.
If you want to take advantage of all the interesting people in a house like Slytherin, because of how active it is, then join away.
On the other hand you may want to be nice and join a house like... Well the other three to help them get more members!
Personally... I reckon Hufflepuff would be good if you were going to take the second option.