Child Spacing

My husband and I have two children, 3.5 and 1, and we're going back and forth over when to try for our third (and last). To be honest, it's me that's so torn. Husband is so flexible, he'll start ASAP if that's what I want. The problem is, my head and heart want two different things. My heart says to try ASAP (January at the earliest), my head says to wait half a year more. There are pros and cons to both.

For those of you with multiple children, what is the spacing and what have been the pros and cons for you? If you could do it over again, or if you could have had an "ideal" spacing, what would you have done, or what would you choose?

Thanks!