The CZ-75B has 17 round capacity, is is about as high quailty as you're gonna find and are not outrageously expensive ( a little over $500,brand new, and I've seen them well under $500 in the last 6 months, at places like Kentucky Gun Store.) It isn't a polymer framed pistol, but they also make those. they also do a compact 75 with a lighter alloy frame. From my personal experience, as well as countless reviews, you simply can't go wrong with one of these.
I've been a Glock owner for nearly 30 years, and they're great, but the CZ-75B is on another level entirely.
edit: LOL, I just noticed you said "striker fired". In that case, look at the HK's, if you want "best", particularly the VP9, which people seem to be raving about (though that SR9 recommended above is an excellent suggestion, and cheaper).