any cool ideas I could build with this data?
replies(5):
People have been post-processing and working on the SRTM1/3 data set for the US48 states for something like the last twenty years, and in some cases combining it with more recent space radar data.
VHF/UHF repeater propagation maps and similar are another application. For both ham radio and public safety system more 'serious' radio purposes.
Or to combine with other data sets for things like population per zip code or data sets on demographic info per zip code relative to the density of buildings, unique structures.
Last mile facilities based ISPs and electrical grid operators and similar can use per-structure data sets like this to do calculations on network build or overbuild/ugprade/augmentation costs for specific geographic areas.