I'm sure this was already covered earlier in the thread, but since the release is now officially on the schedule for October let's consider what might be on the 2nd CD:
1. Pride (Single Version) 4:40
2. Boomerang I
3. Boomerang II
4. 4th of July (Long Version)
5. Bad (Live--WAIA)
6. A Sort of Homecoming (Live--WAIA)
7. The Three Sunrises
8. Love Comes Tumbling
9. Bass Trap
10. Sixty Seconds in Kingdom Come
11. Wire (Celtic Dub)
That's 11 songs, which doesn't leave a ton of room for new/unreleased tracks, but I'm sure there will be something. According to U2Wanderer there are three different versions of Love Comes Tumbling and two of Homecoming Live, but I doubt they'd put all of those on there as the differences are subtle.