I currently have a swoosh 3 wood that I am going to replace with a titleist one but I have a gap between a 4 iron and a 3 wood. Should I get a hybrid or should I buy a 3 iron instead?
Try both of them, because it really depends your ability. My advice would be to get a 19* or a 21* hybrid. Currently I play a 910f 15* and 19* and then use a 24* hybrid. This tends to work best for me because I can't hit the higher iron.
This depends on how consistent you can be with your long irons. A hybrid will certainly be more forgiving, but the some of the better ball strikers prefer the feel and workability of a long iron. You need to make sure you can consistently hit the 3 iron well enough to fill the gap and have good stopping ability into greens.