I don't have a PS4 yet, but some games I'm interested in are:
Transformers Devastation. Neat game, just beat it on PS3. I don't know if I would pay full price for it, but if you loved G1, this is right up your alley.
Gravity Rush Remastered. I beat the Vita version, great game, & there's a PS4 sequel coming too.
Odin Sphere Leifthrasir, complete remaster of the PS2 game, which I have, but never did beat...
Borderlands:The Handsome Collection, I enjoyed the first game in the series even though it does get mundane from time to time. I like the setting, reminds me of Trigun.
Lego Avengers. Really, all the Lego games are cheap fun, however, I would only get them when they're cheap in $
Tales of Zestiria, if you like RPG's by Wolf Team
Tomb Raider(& assumedly it's upcoming sequel), played the PS3 version, great game, & deffinitly worth the $20 it sells for.
Uncharted Collection, love love love these games. Very fun IMO. It's a shame they didn't include Golden Abyss(the Vita Uncharted game) in this collection
Uncharted 4, going off on a limb & assuming I'm going to love this game as well.
Middle Earth: Shadow of Mordor, I'd get the GOTY version.
Ratchet & Clank, not out yet, but, I love the series, so this game should rock. It's a re-envisioning of the original game, & tied into the upcoming movie(also based on the original game)
Fallout 4, the last 2 games were fun, though, take a lot of time, so be prepared. However, I'd wait till there's some sort of GOTY edition with all the dlc included.
Batman Arkham Knight. Another one where I'd wait for a GTOY edition. That's what I did for the first 2, but then the 3rd one never had an edition with any dlc on it...
Final Fantasy Type 0, some say it's a good game, looks like it doesn't sell for much these days.
infamous: Second Son. If it's as good as the last 2 games, then this game is a mush IMO
Rayman Legends, 2D platforming goodness
The Order 1866, I heard it ended up not being as good as everyone expected, but, I LOVE the Steampunk setting, so it might be worth it at $20.