I read alot of manga and manhwa but I want to start reading American comic books, too. Maybe this will broaden my horizons! I'm not too picky when it comes to manga as long as its not too boring or violent/adult(scares me a bit ). Does anyone have suggestions? Or maybe even American manga? What's your favorite?

Do they have to have manga style or anything? Or be the western superhero type?

Lots are quite mature.
Nonmature/less mature ones I can think of of the top of my head....

The Umbrella Academy (I think it's american. Only read the first one, the story's not amazing, but the art is stunning.)
Daytripper (Haven't read, but it has the same artist as above, and I heard it's quite good.)
Unwritten (I don't remember much.)
Scott Pilgrim (love, love, love xD)

Try going on webcomic sites (like Smackjeeves), because lots are quite good.

(Also, shouldn't this be in the "I'm looking for" forum?)

Based on your needs, I would suggest some of the more fringe comic book series like Y: The Last Man. It's a good comic book and although I myself haven't finished it I'm quite certain I will like the ending. I would also suggest Fables by Bill Willingham. Actually, anything published by Vertigo Comics should fit the bill although there are a couple violent comics published by vertigo.

The Sandman Chronicals by Neil Gaiman.
The Arrival by Shuan Tan

and then there are tons of great webcomics out there
The Meek
Manly Men Doing Manly Things
Boxer Hockey
Eerie Cuties
Sandra and Woo
Skin Deep
Ratfist
Sfeer Theory
Grim Tales

And this is just to name the few that I watch and are Pg-13 friendly.

One of my favourites was Hawkworld. It doesn't end well due to editors and the company but its pretty good. you can say the same thing for The power of Shazam series except its less adult.

Daredevil 's series tends to be good. he's kinda like that guy from Till death do us part. Nightwing is a similar series, and that one tended to get better after a writer named Grayson took over. The Moonstone The Phantom series tends to be good too, and you don't need to follow continuity with The Phantom.

The best superhero team book ever is the Justice Society of America.

Some good graphic novels
Justice League of America: The Nail, Justice by Alex Ross is one of the best basic Justice League stories, and the 3 BIG ONES are Watchmen, Kingdom Come, and The Dark Knight Returns.

Try this: www.girlgeniusonline.com It is published online by the authors/artists so no worries about legality or anything.

The Sandman is an awesome series, but it has a lot of sex and violence.

I'm sorry that I can't offer a good recommendation without adult themes (that tends to be the standard for all the American comics I read).

I do second the idea to check out webcomics: there are lots to choose from, and many authors sell hard-copies of their work that you can buy if you enjoy the series.

Transmetropolitan
The Goon
Desolation Jones
The Sandman

By my personal rating system, these are all fun for the whole family, nourishing your aesthetic and mental needs.

Watchmen is amazing. It might fall as a little too cerebral for your tastes if you want something light, though.

Also, the whole Marvel Civil War/Initiative crossover story arcs are a lot of fun to read, even if they are riddled with the usual inconsistencies.

I recommend The Sandman by Neil Gaiman too. I don't like comics with violence either, but Sandman is the only non-manga comic I like (in fact, I don't remember any graphic or violent scenes, but I read it quite a long time ago). If you decide to read it (and I really suggest that you do), bear in mind that the first volume is quite different from the rest.

Don't know how serious you want it to be, but Maus is a must-read if you do like serious comics. From wikipedia:

Maus: A Survivor's Tale, by Art Spiegelman, is a biography of the author's father, Vladek Spiegelman, a Polish Jew and Holocaust survivor. It alternates between descriptions of Vladek's life in Poland before and during the Second World War and Vladek's later life in the Rego Park neighborhood of New York City. The work is a graphic narrative in which Jews are depicted as mice, while Germans are depicted as cats. It is the only comic book ever to have won a Pulitzer Prize.

For a regular old superhero comic, you could always try Witchblade. The comic is a million times better than the anime and manga adaptations of it. (Rather than Americans ruining a Japanese title by importing it, this time the Japanese ruined an American title.) The TV series is also worth a look, though TV Ian Nottingham is pretty different than comics Ian Nottingham. (Still a good character either way.) TV Sara is cool though:

http://www.youtube.com/watch?v=pgtU1C625WA

Civil War and The Initiative story arcs pretty much sucked. I would not suggest those to people just getting into american comics. I would suggest both Annihilation and Annihilation: Conquest. They are far superior and much more self contained to anything Marvel's put out in years. I thought Runaways was pretty awesome. Although the last couple of "seasons" aren't as good as the first two. Planet Hulk is also good.

28 Days later - Actually takes place a couple of months from where the first movie left off. It was fairly good.
The Unwritten - Kind of like Inkheart and Stardust mixed with The Davinci Code. But you know, good.
House of Mystery - If you like weird stories. It serves as a interspacial bar of sorts where you pay with stories.
Madame Xanadu - It was hit and miss with that one. But the good did make up for the bad.
The Sword - One word. Wow. Also, Expect some bloody fights
The Walking Dead - Straight up zombie book. Got a six episode run on AMC. A second season coming in October. Black and white pictures
I Kill Giants - a little girl, who wears bunny ears. Fights giants. Maybe they are real? Art is mangaesque
Y: The Last Man - You will kick yourself later if you don't read it now
Rapture - So all the superheroes leave earth for over a year. Interesting to see what happens.
Coraline - The movie wasn't bad, but I thought the comic its based on is better. Neil Gaiman can write children's stories. Who knew.
Scott Pilgrim -

Megatokyo - Webcomic. It subverts just about everything normally found in manga, anime and galgames. Many longtime readers will tell you it sucks, but that's because they've been reading it one page at a time for a very long time. If you read it in bunches or all at once it does make more sense. the art does get better as it goes along.
Misfile - A boy gets turned into a girl, a girl loses the last two years she'd previously lived. they are both extremely unhappy about it. Also includes street racing.

I could mention more but they are extremely graphic. Extremely graphic.

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Sarcasm just doesn't work over the internet.

I also reccomend MegaTokyo, the art gets better

Aslo, though probably not available on the web is The Good Neighbors, written by Holly Black and drawn by Ted Naifeh. The story is pretty good, though I'm a Black fan.

I'm not much into American graphic novels, but I have read a few. Here's some I liked:

Desolation Jones (8 issues on hiatus for over four years about an ex MI6 agent, lots of violence)
Fell (follows a homicide detective)
Global Frequency (present day science fiction, each issue has a different artist)
Orbiter (near future science fiction about a spaceship coming back after ten years with one survivor, trying to figure out what happened to them)
Singularity 7 (cyberpunk miniseries set on a post-apocalyptic world)
The Books of Magic (a boy discovers there's magic and John Constantine shows him around and stuff)
Transmetropolitan (classic cyberpunk stuff)

A trilogy I have to mention, although it's French. It's also published in English:

La Trilogie Nikopol (Nikopol drops to Earth after being cryopreserved 30 years on Earth's orbit, then meets an Egyptian god Horus—cyberpunk)

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Far-off places with sweet sounding names.

I like Family man by Dylan Meconis
http://www.lutherlevy.com/

It's more along seinen, if you will, about philosophy, possibly paganism and all that, in a certain period.