True Blood does have its original elements, one being that the existence of vampires has now officially been acknowledged by the whole population and the vampires must start their fight for equal rights. Also, rest assured, True Blood's vampires do not sparkle, they have real fangs and they can only leave their dwellings at night. But it is not the vampires from which most of the attraction to this series comes. I found that the theme of the fight for equal rights was very nicely done and something refreshing to see in that context. True Blood takes away some of the mysterious fantasy elements to gain a little bit of realism of what would happen if vampires really came "out of the coffin" in this day and age.
Apart from that True Blood is ripe in blood and sex (although, if you are thrown off my HBO-graphic-level sex scenes, rest assured they get slightly less frequent as the first season progresses) but also offers a dangerous amount of trashiness. I don't think I can ever quite make peace with this aspect of the series, but at least in the first season the trashiness is kept to a minimum. Parts of season two and three were all too overly dramatic and silly for my taste but other aspects balanced that out.
As most series that focus for the most part on the relationship between two lovers, it runs into the same problem after the first season. The couple has found each other... what do they do now? To keep it interesting between the two, obstacles are being thrown into their way on every occasion and thus we are witness to more than one petty, silly fight. This could also be observed in Grey's Anatomy for example. They have finally gotten each other, why must we find reasons for the two of them to fight now? Can't they be happy for once? That is one aspect that does get on the viewer's nerves after a while in True Blood. For some reason the major and minor characters can never get to know a really good person and be happy for a longer period of time.
Another similar aspect takes a bit of the joy of True Blood away as well, this one not a common romance trope but more common to the mystery and horror genre: The beings that are being fought within the series have to get progressively older, mightier and harder to beat. Supernatural followed that scheme ad nauseum, until that series turned from your fun little monster-of-the-week hunt into a would-be epic tale about the apocalypse, angels and demons and shit, alienating a large part of their viewers in the progress. Rest assured, True Blood doesn't quite go down that path as horribly as Supernatural did it, but it does have its tendencies to make the baddies bigger and badder every season.
However, the redeeming qualities of the series still are strong. First of all, the very peculiar setting of the series in Lousiana might appeal to your tastes if you are interested in that area. I started becoming interested in the South when I played Left 4 Dead 2 and I was pleased to find the same landscapes and accent in the series. Just that unusual swampy, rural setting is a joy in itself to behold. Other than that there are the quite progressive themes. Racism among humans doesn't suddenly disappear even though a new altogether inhuman race demanding equal rights appeared out of nowhere. And especially season two deals with the effects of religious fundamentalism in a way that is quite remarkable for an American TV series. Another thing that I just have to mention is that True Blood, while of course focusing on people of slim and athletic build, does also feature characters of a variety of shape and age. There aren't a whole lot of ribs and breast bones staring you straight in the face.
True Blood isn't subtle, it isn't necessarily smart, it can be trashy at times but it does keep you entertained, its characters are engaging and its setting is beautiful and unusual. Give it a go, see if you like it. If you have been looking for new vampire stuff to watch you are probably used to slightly trashy material anyway. Also, did you see? Its opening montage begins with a shot of an axolotl. Isn't that awesome?