Is PSN necessary for me playing games? No
It totally isn't.
The service is horrid to begin with in comparison to either Steam or Live so i didn't use it for online much anyway.
That is absolute bullshit. PSN online plays the same as Live and Steam
The PSN has improved so much in the past couple years that it's 100% comparable to Live now. Sure there are (in my opinion useless) features that don't exist on the PS3 like cross-game chat, but it doesn't make it a horrible service.
Who can seriously argue with the price of FREE?! I know I definitely won't be. I've saved so far $180 (Live) switching from a 360 to a PS3 and not having to pay for any online services. It seems like it's not a lot for 3 years, but to me that's 3 new games to add to my library.
Proud owner of the PSone original, PSone slim, PS2 slim, PS3 slim, PSP-3000.
37 PS3 games and counting.