Fairly subjective, you might get a wide variety of answers in terms of making a selection. A lot boils down to budget and general usage. I'll never stomach spending the money for some brand name ones...they won't make or break my adventures.
I really like the aesthetics of curved light bars that span the top of the windshield. There was one install pic somewhere on NPORA that looked great. But, they're impractical for my application: I rarely offroad at night, and in the situations where I have, I wouldn't be able to use them because I'd just be blinding the guy in front of me. A smaller light bar in a low position will serve my needs.
If electrical isn't your thing, look for wiring kits...they'll usually include the switch, relay, loomed wiring, and crimped terminals. Some will include a water-tight harness, or otherwise be plug-and-play (particularly if the light and wiring are of the same brand). Harnesses that come with Carling switches (those rectangular ones) are a close fit to the rectangular knockouts on the dash, but some modification (by knife or file) might be needed, and you might have some close clearances if using the openings to the left of the steering wheel under the vent...the dash can interfere with the paddle switch operation (at least on the later models they can). The round switches install well with a Forstner bit, which leave a better cut than standard or paddle bits in my opinion. I usually drill the hole right into the knockout piece, knowing that I can replace it easily if my setup changes...if taking this route, put some disconnects on the switch wiring to simplify installation/removal.
As for mounting...this is probably the trickiest part since it's all custom. If the light bar brackets are included (some aren't) using your roof rack rails might be pretty trivial...some slot or square nuts in the channel (probably have the OE ones already in there and unused...I think they take an M6x1?), matching bolts, and some pieces of plate steel or aluminum cut to size/shape would give you some offset mounting options, since the end of the rail is still several inches from the windshield line. If you're willing to drill into the roof and have access to a rivet nut setter, that's another option, as is self-tapping screws into the A-pillar (though probably not the approach I'd take...just be sure to seal any holes with silicone and rubber gaskets to prevent water ingress).
If you want some custom brackets made, I could cut something out on the plasma table, perhaps even get some bends in it. We'd need to talk about some dimensions, of course.