The first thing you should know about me is that I am bery picky about my graphic novels. If the art isn't detailed enough, the storyline is lacking, or the novel is not translated well, I do not buy it. I recommend being the same way about every japanese comic book, because oftentimes they are over celebrated, and in my opinion, not worked on hard enough to be considered art.
The second thing I would like to say is GOD BLESS RUMIKO TAKAHASI! She is one of the most talented manga artists ever. Her style is a little leaning towards the Anime side, but she obviously cares enough about her art to make sure everything is perfect. Her full color prints, (like the covers) are beautiful, and envyed by me and all of my anime cronies. :P Anime is fairly simple enough to draw if you are good with preportions, but is very hard to make look GOOD, so this artist is a rare find!
Her storyline is definately not lacking. Kagome Higurashi is a hirhg-school girl who falls down a well and lands in feudel japan. She meets a half dog demon pinned to a tree (By the woman who he loved, Kikyo, who betrayed him), in a twist of fate, frees him. She later learns of the demon's love for the JEWEL OF THE FOUR SOULS, a jewel that can give the users near limitless powers. Inuyasha wants that jewel, so he trys to steal it. The priestess Keade binds him to Kagome with a single word, "Sit, boy!". In an act of heroics, she decides that she is going to shatter the jewel into a thousand little tiny peices. (It's a longer story than that, but, hey, I've got a lot to write and not much space) Thus making Inuyasha, (who still wants the jewel and to kill kagome) and Kagome, (who's like WTH? I'm stuck in a weird world AND i have to work!) forced to collect the jewel shards.
The books go as follows, until they meet the horrible demon Naraku. Naraku wants the jewel to become full demon as well, (another long story) thus he also is trying to kill Inuyasha and find the jewel. Along the story, they meet a few friends, and the story becomes romantic as well as funny.
If you want to get the full story of Inu-yasha without spending a whole lot of money, I would buy the manga which is beautifully layed out, and wonderfully drawn. If you really don't care, and like watching the show more, I would buy the DVD's in the PERFECT COLLECTION or the SEASON BOXED SET. It is cheaper that way, and you also get a bigger hunk of DVDS.
If you are just experimenting, I would recommend reading up on the story line from a fan site where they can be more elaborite, first. For some reason, a few people don't like it.
Otherwise, have fun watching an excellent Anime/ reading the manga! It's really worth it!