One of the best is 'Pride and Prejudice' (2005). Keira Knightley as Elizabeth Bennet was brilliant. The cinematography beautifully captured the English countryside. Another great one is 'Sense and Sensibility' (1995). Emma Thompson, who also wrote the screenplay, did an amazing job as Elinor Dashwood. It really brought out the essence of Austen's story. And 'Emma' (1996) with Gwyneth Paltrow is also highly regarded. Paltrow was charming as the matchmaking Emma Woodhouse.
Definitely 'Pride and Prejudice' (2005). The costumes and sets were so authentic that it felt like you were transported to Austen's England. The acting was superb across the board. 'Sense and Sensibility' (1995) is also a classic adaptation. It managed to balance the two very different personalities of the sisters, Elinor and Marianne. And 'Emma' (2009) is a great modern take on the story. Romola Garai was excellent as Emma, and it was a fresh and engaging adaptation.
Well, 'Pride and Prejudice' (2005) is a top pick. The chemistry between the actors was palpable, and it made the love story between Elizabeth and Mr. Darcy so engaging. Then there's 'Persuasion' (1995). It was able to convey the poignancy of the second - chance love story in Austen's novel quite well. Also, 'Mansfield Park' (1999) was a good adaptation. It delved into the complex relationships and the social hierarchies that Austen often explored in her works.