Syntax made a good point about the PC library; most exclusives nowadays are smaller and/or niche games. It's hard to think of AAA console-style exclusives that fit your criteria. Most big budget games have been multiplats for years now.
Strengths of PC:
1) Variety. Multiplats, console ports, handheld ports, older PC games, indie games, simulators, RTS, MMO, free-to-play, etc. all on the same platform.
2) Community. People are always optimizing and patching classics, releasing mods, making emulators, picking up the devs' slack for buggy games, and all other kinds of cool stuff (like hacking the Russia-only Halo Online for other regions).
3) Price. Speaks for itself, there are lots of deals if you know where to look-- seasonal Steam sales, bundles, digital game stores for other regions, resellers, etc. Although I will say the same is true of consoles, even if perhaps not to quite the same degree-- something people on here don't always acknowledge. A lot of it comes down to being patient. SW: Battlefront was $59.99 at release last year, $9.99 on Black Friday this year for PC and consoles. Fallout 4 was $9.99 on PC and I believe $19.99 on console. Doom was $19.99 on PC and console.
4) Customizability. A lot of the PC experience can be tailored to fit your needs and budget. Visuals and controls are the two most obvious.
I like story driven games if that helps.
Shadowrun: Dragonfall is one of my favorite games of the last few years. It can regularly be had for $2.99 during Steam sales. If I had to pick out one game to recommend, that would be it.