I think we'll get only one more album after the 2004 release to round their current tri-fecta of albums:
1. Boy
2. October
3. War
4. Unforgettable Fire
5. Joshua Tree
6. Rattle & Hum
7. Achtung Baby
8. Zooropa
9. Pop
10. ATYCLB
11. New Album (2004)
12. New Album (2008)
I think they are done after that.