I'm so happy that you picked Big Fish, an often overlooked gem. It may just be my favorite picture of all time. The other contender for my favorite is Edward Scissorhands, though it isn't really a "feel good" movie, I find it rather melancholy. For that matter, Big Fish always leaves me with the melancholies.

You have Rob Reiner represented by Stand By Me, a great choice. But perhaps a better choice is The Princess Bride. Lot's of Rob's movies are very solid feel-gooders: This Is Spinal Tap, The American President, A Few Good Men to name a few.