Serious gaming question that I really do need some help on. 
 

• What are the best PSN PS Classic games at the moment?
• I own every Final Fantasy, Metal Gear, and Resident Evil....so heads up.  I also don't have the discs anymore.
• Chances of PS4, NGP, and Android being able to log into PSN so I can FREELY download them again?
  

The Crash Bandicoot games are fucking great. The first one and Warped are especially awesome.

Symphony of the Night is up there, that game is AWESOME, and worth playing through again. 

Vagrant Story is supposed to be coming out soon.  Buy that.
Castevania: Symphony of the Night
Final Fantasy Tactics (I wasn't sure if you meant outside of the numbered series or not)
Front Mission 3 *
Legacy of Kain: Soul Reaver *
Silent Hill *
Spyro games
Street Fighter games
Twisted Metal *
Wild Arms games*
 
*I thought these were cool when I first played them.  Don't know if they stand the test of time.
 
I think it's highly unlikely that you won't be able to access the games you buy now on future Playstation hardware.  As long as you hold onto the same PSN account.
 
I still have most of my PSX collection on disc, so I haven't bought any of these games yet.  I can only speak to the quality of the games, not the service that provides them.
 
EDIT: And since I see you're considering PS+, I should let you know that Spyro 2 is free right now for members.

Silent Hill, Crash Team Racing (!), THPS2, Dino Crisis. Um Jammer Lammy if you're feeling funky. Fuckin Soul Reaver.
 
But Silent Hill and CTR you should definitely have.

I own sypro and twisted metal, they are really dated now, but still alot of fun to pick up and play.

" @Spoonman671: I got FFT, Vagrant story I own as disc, and SotN I got on the PSP version.  >.>  Yo, speaking of Wild Arms, never got into them...explain their usefulness. "

Was Wild Arms the game that had like three separate stories. I know one was about a girl training to be a mage but I forgot the other two