Toyo, agreed! The V6's, EVERY SINGLE ONE OF THEM, has had massive problems, including the 4.0. I think Toyota needs to not build V6's, they have a mental block against them.
Now the V8, well the 4.7 that has been in Landcruisers, Lexus', the 4Runner and the Tundra has been rated the most reliable engine time and time again.
As for the more power, for towing etc it won’t be much better at all. Where my 4.7 seems to pull hard and the slow up a little on the top end the new one probably just keeps pulling. IMHO it is not worth it. However the day you buy an 04 it will be worth allot less than if you had bought an 05. It really comes down to person choice. Are you going to always be saying "I wish I had an 05" or, if you want more power and had an 04 would you just add a TRD blower down the road and be ahead of the game? I would look more at things like the new rear wing, is the insurance different etc. Good luck, you cannot go wrong with either V8.