Hiya Sparkly!
Congratulations on your engagement.
I'm another already married one. We got married in November 2005 in a castle up in Scotland.
We didn't have a particular date in mind but the venue we wanted was cheaper at that time of year. We originally booked for the september but then thought about how much cheaper it was a couple of months later and then changed it to November. So cost was the main reason we chose our date but the more I thought of it the more I liked the idea of a winter wedding with candles, roaring open fires, lovely hearty food, fur wraps etc.
Also you can never be sure of the weather particularly in Scotland so even if we had chosen a date in the middle of summer we wouldn't have been guaranteed to have nice weather anyway. So by choosing November we had no real expectations that the weather would be nice so we wouldn't be disappointed if it wasn't if that makes any sense! In the event it was a gorgeous clear frosty day (a bit chilly though outside!)
We got married early in the afternoon and still had plenty of time for photos outside in natural light.
The date you choose may not have any significance to you beforehand but it certainly will have after you get married, no matter what time of year you choose.
Look forward to hearing all about your plans!