Well, a "floodgate" would be an overstatement, but quite often I do take note of what to do next. The base stories of my "Secrets of Dyrt" and "Star Story" were written around the same time and for me it was just the choice which of the two to develop first. Now I must also say that some ideas I start on, but never finish. Well, I guess in that regard I'm not that much different from the professional industry where that happens a lot too.
Of course, we may all suffer some times that we don't have any new ideas at all, and then picking up some ideas you already had noted before can be a nice option. My game "Luna's Father" which has being developed now already had a few notes when I was working on the two games I mentioned before.
In the end we must always make choices what we do and what we don't and especially since game creation is quite time consuming, I guess that counts here even more.
And yeah when my game is in the final stage, it always bothers me. Then I'm really though with a project, but the number of bugs popping up seems to be infinite. And when I am already wanting to do something new, that's even more troublesome. This struck me especially between Star Story II and Luna's Father, as the latter has a complete new engine from scratch and therefore I needed more preparations before I could get onto the project itself. Oh well.