For certain definitions of reusable, yes. Certainly retaining the SSME's for refurbishment was a big accomplishment. I wish Energia+buran could have maintained

For certain definitions of reusable, yes. Certainly retaining the SSME's for refurbishment was a big accomplishment. I wish Energia+buran could have maintained funding for a few decades - concepts for the flyback boosters were cool and possibly promised to be more quickly/reliably reusable than the space shuttle ended up being.