I've started planning out a Scorched Earth remake. I work 7 days a week from 9am-10pm, so I haven't touched DBP since April, so all the planning is done on a pad of graph paper
I am still deciding whether to do it in 3D or 2D, or maybe a bastardized 3D/2D combination. I don't think destructable terrain is as hard as some people say it is. With any project, I take a look at what will be the trickiest logic part and draw it out on paper. That way I don't waste a bunch of time with dummy variables and such and I find I produce cleaner code.
I'm also thinking of different things to use rather than tanks.