I have to agree that my 2nd floor laundry is the best part of our house! I am also a big fan of open floor plans. My least favorite thing is lack of a formal dining room. We skipped it in lieu of very large other downstairs rooms, and I'm not sure I would trade that still (I LOVE how open/large our family room and living room are), but it would be nice to have it all!

I guess just consider your needs in general -- do you need/want a formal living room, or is just a single family room/great room ok? Do you need a formal dining room, or is a large breakfast room ok?
I also like, and wish we would have gotten, a breakfast room/sunroom off the back, just sort of to increase sitting space in or off of the kitchen. We end up hanging out in there a lot, especially when we're entertaining just family and have food everywhere, and I'd have loved that.