I just finished watching the latest BBC adaptation of Northanger Abbey...(yes RJ, I went snooping around in your DVDs yesterday)...and I must say I was quite delighted with it. The ending went a bit too fast, but the beginning was perfect. Austen's beginnings are usually quite important, and Northanger Abbey has one of the funniest. The whole book, of course, is a parody/satire of a Gothic Novel and this adaptation totally embraced that. Catherine's imaginings work quite well on film- I only wish that the running time was longer!
Of course, I should also add that since some actual Gothic novels are narrarated onscreen, this adaptation is not as suitable for younger viewers as the book is. However for us older watchers it's quite fun! Henry Tilney is without a doubt the most humerous of the Austen heroes, and Catherine Moreland is in many ways the most *normal* young teenager of the Austen heroines (the youngest of all, I believe). Her naive assumptions and wild imagination give this whole story much more interest than a normal Austen book. Unlike the other five novels, it does not dwell wholely on the functionings of society, since the purpose, of course, is to poke fun at the Gothic novels that were popular in Austen's day. It's also the shortest book (and film adaptation) which makes it a good introduction to Austen for a newcomer- or someone who doesn't want to tackle the finer works of Emma or P&P yet.
The only drawback is that it's harder to find these new BBC adaptations, which is quite the pity. I wish we Americans had a similar production company to make sure that our population continued to get exposure to the great literary works of our country. (Not that we have quite the same level of humerous romance- Little Women is about as close as you can get here!)