MAX!!!!!
Ok, now that I gave my answer, let me qualify it by this. The Max is clearly a more powerful car (265 HP vs. 240 HP). It also is larger and more luxury oriented then the Accord. Normally the comparison is made between the Accord and the Altima, not the Maxima. Bottom line though is unless your wife (or you) really need that extra 25 HP, just drive both and see which seems right to you. What is right for me might not be right for you. They both are very nice cars and reliable and well put together. If you are planning on getting Nav in the new car, I hear that Nissan has a better Nav then Honda, but I haven't used Honda's.
BTW, if you get the Max, it will give your GTP a run for its money... :-)