Never seen them. So yeah I would see them regardless of the album. I won't be there for the new stuff though, unless it's up to the U2 standard, which the last three albums haven't been.
I think this is a pretty self defeating idea, as they always play the new songs more vigourously, just like they did last tour and all the tours before. It's just a rule, they give their all to new songs. The big '80s classics have usually disappointed since Popmart, with the exception of Streets and Follow, and Bullet, up to and excluding Vertigo.
As for the substandard album thing, while I don't think NLOTH is a good U2 album, it's certainly a lot better then the tour following it turned out to be. I was excited by the record, at least for a month (in contrast to Bomb, which I found mediocre instantly) and couldn't wait to hear the more interesting stuff live. With the realization that my then fave Crazy was not going to be played at the shows in favour of the lame Mofo substitute remix version, that had little musicality to it I already felt shot down, and then they teased other favourites of mine in rehearsal, they ended up omitting. After contemplating for a while, listening to friends' reviews and broadcast gigs, I chose not to go to see 360° as it felt like a U2 show put together by some Disney marketing suit, with a feeling of half-steam performances coming through most recordings, and an unsatisfactory setlist, which was a new and wearysome experience (especially after the powerful Letterman stint and similar TV performances). Then came Bono's surgery, and the new shows were nothing short of warmed over nostalgia fests.
I've seen them live on Elevation (awesome first show) and Vertigo, and though Vertigo wasn't too exciting (due to bad standing places in both stadiums due to screw ups getting to the gigs), it felt like a 100% rock-show, with actual excitement and warmth. I didn't feel the urgency of a U2 gig with 360° at all, plus the stage design alienated me to some extent.
Will I go to their next tour if I don't like the new stuff? Depends on what makes the rest of the setlist, and if they perform better than on 360°. Also I probably wouldn't want to see them in a stadium.