I've never understood why so many people seem to hate Ben Affleck. Granted, he's made some stinkers, but he's also made some good films, things like Chasing Amy, Shakespeare in Love, Bounce, Good Will Hunting, Dogma, Jersey Girl, and Hollywoodland. He always comes across as a likeable guy, and is quite willing to kid his own image (as in Jay and Silent Bob Strike Back).
He's a bit limited as an actor (though Hollywoodland shows he does have enough range to put out a fine performance), but there are many actors who are similarly limited. It may be the whole Bennifer thing -- his appearance as a tabloid superstar turned a lot of people off to him.
Forces of Nature is one very nice film, and a good role for Sandra Bullock, to boot. It's faint praise to say this is Bullock's best role since Speed; her career since them has been one dismal film after another. But this is something she can also stand out in.
The film is in many ways a remake of Planes, Trains, and Automobiles, a movie that is somewhat overrated (good, but not classic). Ben Holmes (Affleck) is flying to Savanna, GA, to marry Bridget Cahill (Maura Tierney), but, after a series of mistakes, he is forced to travel with Sarah Lewis (Bullock).
It's a road picture, as various problems make the trip both funny and complex. Ben finds himself becoming attracted to Sarah as they make the journey together. He's a conventional sort and he finds her more freeform approach to life very appealing. There's a nice chemistry between the two; you can see Ben's attraction grow.
The movie is smart enough to come up with an ending that is somewhat surprising given Hollywood conventions, but also perfectly reasonable and emotionally right.
Maura Tierney is also good as Bridget, who knows Ben better than he does himself. Tierney at this point was best known for her role on Newsradio, and seeing her as the dramatic center of the film was quite surprising at the time. This is a fine romantic comedy with a twist that really makes it stand out.