BIG MAC XXL  This is a fine and my favourite Bible study software. It still has obvious bugs, but it runs smoothly most of the time.  
(Version 1.3.5)

BIG MAC XXL  Since my upgrade from Tiger 10.4.11 to Leopard 10.5.2 Enigmail 0.95.6 freezes my Thunderbird 2.0.0.12 all the time when hitting Reply. And those mails are text-only and without any encryption.

On Tiger no problem at all, Enigmail runs perfectly. On Leopard PGP/GPG with Enigmail becomes unusable. Beware switchers!

This problem is already known in the Enigmail web forums. I hope there will be a solution soon.

This problem might only occur if you are running a PowerPC Mac, although I heard otherwise. A friend of mine with an Intel Mac has no problems at all.  
(Version 0.95.6)