Originally Posted by 7055
1) what to look for in the sport jacket
Fit. Nothing else is as important.
2) the type of shirts to wear it with (I was thinking OCBDs but maybe that's too casual)
An OCBD is fine. It is most definitely not too casual to wear with a sport coat with jeans (but see below) and no tie.
Frankly, it's likely be okay to wear even with a sport coat, real pants, and and tie.
Some folks even see nothing wrong with an OCBD with a business suit and tie. Although I'll grant you that that's more of an American style thing, than it is European. And not even universally an American thing. And you haven't indicated where you're located.
3) and the trousers.
Yeah, about that jeans idea of yours...
If you're young - like, younger than a 22 year old college graduate - and you want to wear blue jeans with a jacket for that "My jacket shows that I'm comfortable dressing up, but my jeans show that I'm not stuffy about it" look, go ahead. I won't like it, but you're young, so I can ignore/forgive much.
If you're older than that, but still in your 20's, and you want to wear chinos with your jacket, go ahead. It's not generally a great look (in my opinion, of course), but at least it's not jeans. And you're still within 10 years of having been a school boy, so you can get away with chinos here.
Otherwise, wear real pants. Wool pants. Light weight, winter weight, whatever. Okay, if it's cold weather, maybe you could get away with wearing cords. Or if it's summertime, and you like linen pants, fine.
4) Also, I'd like some thoughts on color combinations, I am not opposed to Navy, but it is so common it is borderline boring.
The thing with a navy sport jacket, is that if you already have a navy blazer, a navy sport jacket is just another navy jacket. Not that I'm knocking navy blazers - or even navy sport jackets. Just pointing this out, is all.
Charcoal is not much better, but at the same time, I don't want to look like a goon or get something that's not versatile enough.
I have nothing against charcoal suits, but charcoal is pretty conservative. And a sport jacket is nowhere near as conservative as, say, a business suit, so charcoal seems like a questionable choice. Although exceptions exist, of course.
Anyway, that's why I prefer light or medium grey jackets, to charcoal ones.
However I'd like to consider something other than the navy sport jacket paired with a lighter shade of blue shirt that is so unbearably common.
So wear a navy sport jacket with a shirt that's pink. Or one that's white with a fine yellow stripe. Or with a pair of seersucker pants. Or with all sorts of other things which will leave your overall appearance decidedly not "unbearably common," even if a navy jacket is far from wildly exotic.
Or don't get either a solid navy or solid charcoal jacket. It's not like those are the only two kinds of casual sport jackets on the market. There are tweeds, and tan, and navy window pane, and olive, and so forth. I can't tell you which to get, as that depends on your taste and preferences.