I love
Ivan even though it's super common here (as are all it's forms:
Ivo, Ivica,
Iva,
Ivana,
Ivona,
Ivanka,
Vanja....).
I'm not a fan of
Radoslav, but
Ivan Radoslav makes a nice combo. The only
Ivan with a middle name I know (we don't use them in Croatia) is
Ivan Augustin.