It was def Fire Emblem that convinced me to get a 3DS x ) Other franchises would be Pokemon and... that's it for handhelds...

For consoles, it has to be Smash Bros and Mario Bros x )

If we were talking genres though, it would be RPGs in general that interests me in buying PS consoles.

Zelda and Metroid. Don't ask me why I bought a Wii U.

MGS, uncharted, Dark souls series and WRPG games like dragon age, TW3, etc.

Mostly all nintendo titles, especially pokemon, zelda and metroid also mario

souls, monster hunter

i generally buy the nintendo systems because i know they'll have quality first party games in general but I wouldn't say mario and zelda are system sellers for me if that makes sense

Handhelds: Pokemon (main series)
Home Console: Mario Kart or Smash Bros.

I never would have gotten into anything next gen if I didn't see a Link Between Worlds, so Zelda. Smash is also a system seller for me. And Persona 5 is making me get a PS4.

The portly plumber always convinces me to part with my cash.

Nice to see a brother here, but I'd also add Bayonetta and The Wonderful 101, PlatinumGames projects definitely raise my interest for determinated machines. 

Pokemon, for handhelds. Anything else for the consoles. A metroid, a Zelda, a F-Zero. Mario, not really. PS4, anything Naughtydog works on. Plus, the rest of the games Nintendo doesn't get.