The Wedding Singer (1998)
Admittedly, the best part of this movie is at the end when Billy Idol shows up on the plane but overall this was a really good movie and would probably end up on a best of list for Adam Sander as well...maybe.
Barrymore plays Julia Sullivan, the lead character opposite Sandler's Robbie Hart.
No Oscars or Golden Globes for this one. Obviously the voters do not appreciate good film. LoL!
Ever After (1998)
Barrymore received a Saturn Award for Best Actress (whatever the hell that is) for her portrayal of Danielle de Barbarac in this film.
The movie itself was a pretty cool rendition of the Cinderella story. The only downside to this movie was the actor they had playing the prince (Dougray Scott). Never been a big fan of this guy. Drew, however, played her part amazingly.
Fever Pitch (2005)
Okay, so for #3 best Barrymore movie, it was between this one and 2004's 50 First Dates (another movie where she played opposite Adam Sandler). I went with this one mostly because...well...you can't go wrong with the Boston Red Sox.
In this one, which was called The Perfect Catch outside of the United States (which in my opinion would have made a much better title), she plays the lead character, Lindsey Meeks, opposite Jimmy Fallon's Ben Wrightmen.
This movie was based off of a Nick Horby novel, whose novel's High Fidelity (also a really great flipping movie) and About a Boy have also been made into movies.
In fact, this particular novel has been adapted to film twice. This one, released in 2005 and another released in 1997 which was much closer to the story in the book. In the book, the main character is a big fan of a soccer (or as most of the world calls it, futbol) team and not a baseball team.