Subjective, but I like Auto Finesse Crystal Glass Cleaner for inside and out. Sometimes use Autoglym Fast Glass too.
Occasionally use Rain X Rain Repellant on windscreen, which beads lovely but find it often makes wipers judder and squeak so now I tend to leave front windscreen free of anything, after cleaning. All other exterior glass gets waxed along with bodywork, so whatever wax I'm using at the time.