We're still quite a ways from retirement (20 years), but DW and I talk about this all the time. I would love to take off for 3 months to get away from the cold and snow - golf, walk, be outside, etc... She is less into the concept. I think the compromise will likely be 4-6 weeks (in 1 or 2 stints) in January-March, but we'll see. Like others, I get very down in the cold days of winter - I just can't stand it. I don't necessarily need to be gone for 4 months, but I need some breaks built in.
Even before retirement, once the kids are out of the house I expect that much of my personal vacation time will be taken in January and February. I just want to get away from it at this time of year!