What should I replace my garage with?

[realist]

My first choice if it was me would be to rebuild it with a loft/apt above it. Check the zoning and such to see if that's possible. Even just as an unfinished space it could be used for storage in the short term, ande ventually become an apt, an office, man cave etc. Second choice would be some kind of "grassable" parking surface.

[OhGreatGuru]

It might make sense financially, but you are into a whole different level of capital outlay. (Water, sewer, power, heat, building has to meet residential standards of construction)