I'm planning on running Barcelona too. My wife's from just outside the city, and her family still live there, so it's a perfect option for me. Other than getting up at 5am to get to the start line in time that is...
Flights are booked, but haven't entered yet because the price hikes for later entry aren't as high as the chances of me injuring myself between now and then... Will enter in late Jan unless something goes horribly wrong. Otherwise it's just a relaxing family holiday.
Aiming for 3h10 (no prizes for guessing why that's my target), which seems achievable after a sub 90 half in St Albans in June. Everything went perfectly that day though...