If it's between funding a thousand MSL-style probes and funding ISS, I'd vote for shutting down ISS. I was never a big fan, it sucks research cash but doesn't actually do much science. It's so bad, ISS people need to find people doing very stupid experiments on it when you can't get time on any of the scientific probes since they're so crowded with research. Just a comparison of the papers released from experiments from ISS vs experiments from any other probe (say, a fringe experiment) like Galex, I'm not even counting the papers from the real telescopes like Hubble show how useless IIS for science.
Even medical science... There's really not a lot of research coming out of it.