i'd recommend bloodborne, i don't like dark souls AT ALL but i loved bloodborne and plat'd the game. and i have the reactions of a 90 year old man, so if i can finish the game anyone can. you can wait though, the xpac was just announced so maybe there will be a GOTY version
i love gta5 on ps4, its really fun in multiplayer. driveclub is currenty $20 on sale for PS+ members including season pass, its a good driving game if you are into that. witcher 3 is obviously GOTY contender so definitely that.
i wouldn't go nuts on getting too much, just something like Destiny and MGS5 will suck up 100% of your gaming time. maybe renting something like until dawn for some casual time with friends/family. Diablo 3 was on sale for $28 on PSN dunno if it still is.
also get a PS+ sub, you need it for multiplayer and the 2-3 games they throw in per month for free (indie crap 99.9% of the time) are sometimes fun.
rocket league is one of the awesomest little indie games and you can just play it over and over (multiplayer). i'd wait for sales on other games, PSN runs flash sales all the time. for xample I picked up the entire telltale games collection for $35 this spring, it is a lot of pretty awesome story telling for $35