In regards to sparring, I personally like to take a strong Offensive Defence. I find it easy to defend against attacks, especially the first few in a string, and the openings your opponents create on themselves are great. I find that (personally) it is easier to do more damage when I am on the defence. Counters make for great openings and leads, and I find take downs are pretty easy when your oppenent makes themselves fall over your foot or hip.
Now in fighting, (although i dont go out and pick fights with strangers) I seem to feel that I would lead with a strong defensive offense. I am not sure why I feel this way, it may be the kill or die mentallity at work, and of course it would depend on my on the spot determination of my opponents skill level and fighting capability. (always expect a good fighter for one)
How bout you?