Sampled both Discovery and Homework on Amazon. Went with Discovery for the time being.
Homework has a been of a more rugged sound to it but this is one of my favorite song from the album:
http://www.youtube.com/watch?v=XZSj3FbdFa4
I also love how the album has Revolution 909, Da Funk, Phoenix, Fresh, and Around the World all consecutively. I fuckin love those songs.
Start with Discovery....then go to Homework.....then top it off with the best of all. Alive 2007. If you're still hungry go for Human After All afterwards.
No you should listen to them in order of release date imo. Also you won't appreciate Alive 2007 as much if you haven't heard the albums separately first.
Don't forget about Alive 1997! Too many people sleep on it.