Kagamin for me still!
I like her design, her tsundere antics, and she's just so cute when she gets caught doing things she's embarrassed about. Ex: the fan thing, loving food (like me) / worried about being fat. I also tend to like the characters with the common sense too since it sets up hilarious situations when they're paired up with the more, *ahem* unique characters, which is exactly what Lucky Star was mostly about.