I will say that I have become a huge fan of the TV Series as well as its spin-offs. I also think that the TV Show starring Sarah Michelle Gellar is a superior piece of work!
That said, this movie is not bad at all! You have to look at it as what it is: A prequel to the TV Show. If you watch the first episode of the TV Show it references much of what happened in the movie. Much of Joss' original ideas were reworked into the TV show, but the film is where these ideas first came to life.
If you look at the Buffyverse as an evolving entity, it's easy to accept this film as a companion piece to the subsequent representations. If you attempt to compare the TV show to the movie as if they are in competition then you will be disappointed. Try to think of this as the beginning, as the TV show has done. You'll be a happier fan.
I love this movie... not as much as the TV show, but it's still a hell of a lot of fun to watch, and a great intro to the TV Show. This film is to the series what the Hobbit is to the Lord of the Rings.
Man, I'm a nerd! Three Stars for Buffy the Vampire Slayer! Five stars for Kristy Swanson just for being hot!