Maybe I'm in the minority, but I don't see anything wrong with Iron Maiden trying to make as much money as humanly possible on their catalog. It's is not as if they have "sold out" musically -- A Matter of Life and Death was a great album, and their decision to perform it in its entirety on their world tour was a brave and counterintuitive move -- so what's the bother? If they ever release an album consisting largely of radio-friendly power ballads, like Metallica did, then I'll accuse them of selling out, too. (Sorry for that jab, Black Album fans.) But for now, more power to them.
I also am confused as to how this hurts people who enjoy collecting Iron Maiden's discography -- if you're one of those people, why wouldn't you be delighted to have something else to collect? Moreover, as someone who likes to make "mix" CDs and playlists for my car stereo and iPod, respectively, I appreciate the live "single" versions of Churchill's Speech + Aces High, as well as Phantom of the Opera, and I may download those tracks even though I already own Live After Death. (I did the same thing with Fear of the Dark from Edward the Great, even though I already owned Rock in Rio.) I probably won't buy the entire album, but that's me -- others might.
I think it is fair to say that Iron Maiden are as popular now as they have been in the last 15-20 years, and a new release targeted at younger fans who are showing interest in the band is just good business. This is true even if the same arguments were made for Edward the Great six years ago -- some of the fans I saw at the concert last February were probably still listening to The Wiggles when EtG was released. Why not try to hook in new fans with a new "Best Of" release, some of whom will then buy up the rest of Iron Maiden's catalog? Iron Maiden is "hip" now -- they weren't hip when they were touring club dates with Blaze Bayley ten years ago, and they may not be hip again in 2-3 years' time. In some respects, it would be moronic not to release something to coincide with this year's tour, other than simply the Live After Death DVD. Go get 'em, fellas. And get that Maiden England DVD on store shelves soon, too.