Don't use wav; flac or alac, it's your choice. They're both fine. I'm a mac guy so I've always used alac. But lossless is lossless and you can easily change the format. ITunes only works with alac though which is why I recommended it.
"So to your third point, If I rely on the computer DACs will it sound lifeless? I'll spend a little money if I have to. and my current daily user laptop is a couple years old and I am always willing to upgrade a laptop. I have three kids to give leftovers to."
I like the dacs on my macbook and ipod just fine. YMMV; there are plenty of good headphone amp/dac combos. My point is that if you get a pair of cans that are easy to drive (like the AKG 550 but there are plenty of others), you don't need the amp/dac and you can always add one later.