I was hoping Gnu would post his macro guide. :P
Honestly, I only use two macros on BLM:
1) Virus that has a /p line in it to coordinate with others on when to use it
2) Eye for an eye to coordinate with others on when to use it
That's it. :\ I've found it's easier to just hit every single ability/spell.
Alright. I've spent enough time at Level 50 to know which ones are critical, and which ones don't work. I will make the Guide later tonight and post it here.
The only issue is that the way I have them setup, you have to know how to use the macro to make it do what you want. Every great now and then, maybe every 200th cast, my main macro pops out a Blizzard III at the wrong time. Considering how many mistakes the macro has saved me, this is a decent trade-off in my book. I'll just have to explain that in the guide.