Really hard to give a rating to this show, since it's about nothing. Lucky Star is a slice of life show by Kyoto Animation with a number of notable qualities: it was one of the first major discussions of otaku culture that gained significant popularity in the west, the art style is highly recognizable and the series was wildly successful. Personally, it was the series that taught me the words 'moe', 'lolicon' and 'fujoshi', as well as introducing me to tsurime. It still remains the only series I have seen with a character who is an American otaku. If you're familiar with the 'X is mai waifu' meme, Lucky Star fans originated that during the show's first airing, proclaiming otaku loli Konata to be their waifu.
But really, it's about nothing. The characters talk about whatever's on their minds. Though doing so they reveal quite a bit about their personalities and what they think various things and each other, and that's kind of fun. But there is no drama, no plot, no progress and no development. If it weren't so deliberate I would criticize this, as it is it's more a factor that prevents the series from being 'genius' and leaves it as simply 'entertaining'. It features dozens upon dozens of references to other anime, most especially the Haruhi Suzumiya series, which it aired shortly after, and shares a number of voice actors with (not to mention being made by the same studio).
Lucky Star is the sort of show that so long as you know what to expect (and are interested in that) you'll probably enjoy. The writing is clever, the characters are entertaining and even a westerner will have a lot of moments of thinking 'yeah, that totally happens, heh'. If the idea of just watching girls talking about whatever doesn't appeal to you then you shouldn't watch it.
