This season is my favourite as well, with all my favourite couples together and all. There were so many passionate moments, and I was glad to see that all the Scooby - members were getting more and more mature (except for Giles, of course). Also, this season included my favourite "big bad enemy", the Mayor. (I can't help it but I just love that guy. 😀 )
Now, since I share the funniest and the most impowering moment with Slayer Comma The, I just want to mention the saddest. Or, at least, I wanted to mention it... I say "wanted" because I simply can't find only one. Almost all the Bangel moments broke my heart. Their conversation on the hilltop in Amends, Buffy leaving Angel when he can't say he doesn't love her in Lovers Walk, Angel's dream about marrying Buffy in The Prom - these were the most heartbreaking moments (they always made me cry and feel hollow inside afterwards), and they are only just a few to mention. Even though they were so painful and real sad, I loved them all. I've always seen season 3 as the culmination of the Bangel relationship with all there emotions coming to surface.