I'd recommend you searching (or maybe posting in) the regular Trees Discussion Forum for ideas on what to plant. Specifics (climate, site conditions, size requirements, etc) about the location would surely be useful.

In many (most?) locations, the neighbor would be liable for replacement costs of your trees (possibly a considerable sum of money) if you could show that his actions caused the death of your trees. Might be worth checking into if it's not already too late (looks like you have already started removal).