Please note that I have nothing against Bella and Edward being together. But there are some factors going against it. Here's a few I picked up from the Book (I also saw the movie, but rather reference the book).
WARNING: IF YOU HAVEN'T READ THE BOOK (OR SEEN THE MOVIE) AND DON'T WANT TO FIND OUT ANYTHING ABOUT IT BEFORE YOU DO. DON'T READ ANY FURTHER. YOU'VE BEEN WARNED.
1. He dumped her in the WOODS (or by it, however you place it). Seriously! I don't care where her home is you dump a girl accidentally prone like Bella in a building. And in her case one where there's a lot of people. I mean for goodness sakes she ran into the woods after him and got lost. Not a very smart move Edward.
2. He caused her to go into a deep depression after he left her. She was robotic in life and just went about her day automatically in a living dead stupor. Taylor and her father had to work over time to bring her back. And remember the screams (the movie made them even worse)?
3. Bella's life was a lot less complicated before she met Edward. Taylor may be a werewolf but he's a lot safer than Edward (in my opinion). He doesn't have any enemies except vampires who make their way into Forks and cause trouble. Plus he has Bella's father's approval. Family is very important. And hint, hint, who do you think can give her kids? New Moon only points to Taylor.
4. Edward's lifestyle is way too dangerous for Bella. The Voltouri's a lot more dangerous than The Pack. And the Voltouri wants Bella to either be turned into a vampire or killed within an unknown time frame. Being placed between a rock and a hard place, much? I mean seriously, The Pack only wants their members to be happy and safe.
5. And lastly, Bella's infatuation with Edward is just plain unhealthy. With Taylor she tries to see the full picture (especially since she doesn't want to hurt him). With Edward...yeah, she's like a horse with blinders on. She can't focus on everything in front of her. Especially the risks and consequences. Plus in an interview even Robert Pattison condemned this aspect of the relationship (he doesn't like relationships that lienate family and friends).
So that's it. Please comment after reading and let me know what your views are.