Woo! First one to post and vote.
So, my selections were Konata, Kagami, Minami, Misao and Hiyori.
1.) Misao - Her voice and character for the absolute win, naaaa~. Her seiyuu could read the phonebook and I'd be in stitches.
2.) Hiyori - An episode of Lucky Star just isn't complete without a Hiyori yuri-flavoured fantasy
3.) Minami - I don't really know why I like Minami's character and it frustrates me that I can't pinned it down, but there you go.
4.) Kagami - She's so full of wonderful bitey snark that I just love so dearly. She's the ideal straight-man to Konata
5.) Konata - Aya Hirano really deserves props for the way she's developed Konata. She's so outlandish and random that it's a joy just to watch her on screen, especially when paired with Kagami.
Kuroi sensei gets an honourable mention for her sniff.