Well, they can do a Nostradamus tour and play 3-5k seat venues. They can play all of an album and play those same venues. Or, they could take out some other good bands and do a greatest hits show in front of 15k. They always managed to throw in some chestnuts, so a greatest hits show wouldn't bother me. If they're going to do an album, they should probably do Screaming while Rob still stands a chance of pulling it off--the clocks ticking on that one.
If somehow they did their U.S. tour to coincide with Iron Maiden's off-months early next year... and they toured together... oh God.
But realistically speaking, the only two other bands that came to mind are Def Leppard and Van Halen. Not sure what DF's bren up to, and I know VH is supposed to tour next year... so...
I'M ELECTED, ELECTRIC SPYYYYYY
I'M PROTECTED, ELECTRIC EYEEEEEE
EDIT: Motörhead announced a 2011 U.S. tour a couple weeks ago... what if Priest and Motörhead toured together!!!???
EDIT2: Didn't that already happen with Heaven & Hell and Testament?