I dunno, do you really want your wife to dictate that all movies will look like soap operas for the next X years??
I personally can't stand the "flat" look of LCD's -- even though they are really bright, it always looks a little "digital" to me, no depth and richness like plasmas.
I just went to a local Best Buy / Magnolia at lunch today. They had the Kuro 5080 and 6010 directly adjacent to the 58pz700U and two nice 1080p 52" LCD's (from Sharp and Samsung). The LCD's give that initial "pop" because they are tuned so freaking bright, but when you would see a closeup of skin, like on a tight face shot when someone is talking, just the depth and richness of the skin tones was so obviously superior on the plasmas. I love that rich, natural look, but to each his own.
Frankly, looking at the 58" 700U, the 5080, and the 6010, I couldn't see a lick of difference between 1080p and 768p, even at 5 feet. That wouldn't influence my decision at all.
The question is pretty simple: do you NEED to have the blackest blacks? Even under the bright lights of Best Buy, when the scenes would fade to black or when they would show a dark scene, the difference was fairly obvious. I thought this gave the Pio's extra richness and saturation, especially with skin tones. However, other than that, you'd have to look really really hard to see much difference. They are all excellent displays, it's a matter of budget vs. size vs. black levels.
In the darkened Magnolia section, they had an 1150 (768p Elite Pio) next to a 50" PZ750U, and the difference was still there, but again, they both looked awesome. You will probably be very happy either way.
How far will you be sitting? That could make a difference too. The size boost may be worth it, as a 58" is WAY bigger than a 50".
PS - as far as the whites on plasmas, no, they will never be as bright as LCD's, but when you are in your home in the more normal lighting of your living room, I highly doubt you will ever consider a plasma "dim". Do you really want to stare at a shining bright light all the time?