It depends what you are planning on using it for. However, I would advise for full SSD or at least a 2TB Fusion Drive for a more enjoyable computer experience regardless of what you are using it for.
I got the SSD. not a believer in Fusion drive. Just want to work with it and play an occasional WoW game. have not had a computer to play a game in over 4 years.
I don't think you're going to be disappointed with the new iMac.
How about saving this thread... and giving us your impressions once it's up-and-running?