top 10:
1. nwra
2. deer park
3. steppin' out
4. before the moon falls
5. middle mass
6. fiery jack
7. athlete cured
8. green eyed loco man
9. wings
10. barmy
I think "Wings" needs to probably be higher on that list. I think that's the best riff ever. Sometimes I'll sit and play it for 10 minutes at a time.
http://www.youtube.com/watch?v=wwrBE2n5xGA
I'm sure it's unpopular but I think "Reformation" is one of their best songs. 0-3-0-3-0-3-0-3 on the lowest string for 7 1/2 minutes and somehow it's amazing.