I have just been down the 2 or 3 road, really struggling with the decision whether to go for number 3. I had a big issue about age gaps, and didnt want there to be a big gap between DS and #3, I fel rushed and pressured and quite honestly I felt very very paniced. However, due to work, which I LOVE LOVE LOVE, I have decided to put having #3 on hold for a while- I need to finish my next 2 month contract before I can take more maternity leave.
Now I am much more relaxed about having #3, yes there will be over 3 years between DS and #3 , and nearly 5 years between DD and #3, when there is only 18 months between DD and DS, but at the end of the day what difference does that make- they will all be brothers and sisters, and will love each other regardles. DD will be at school fulltime by the time I have the next one, and DS should be toilet trained and much more independen, which I think will make life alot easier because having the first 2 close together was lots of work.

So I guess where I am coming from, is there is no rush to make a decision- enjoy having just 2 for a while, I think deep down you will know whether having #3 is right for your family or not. Some very wise once told me that you will never have enough money and there will never be a 'right' time to have a baby, but your heart always knows ! Good luck with making the decision.