Judas Priest are fucking excellent.
So like many bands, they've got a "golden era" - I'd say that 3 albums that fall into that category would be: Defenders of the Faith (my personal favourite of theirs), Screaming for Vengeance (pretty close up there), and I think the obvious mention in that golden era (although it's my least favourite of the 3 I'm listing) would be the British Steel album. It's probably more pop-y than their other albums, but it's got some quality tunes on it and it's iconic and their best selling album for a reason - it's a strong album with catchy songs.
Aside from that "golden era" - I'd also say Killing Machine, the album before British Steel, is definitely worth a listen - I personally like it a bit better than British Steel.
Other than that, you've absolutely got to give the Painkiller album a listen. I'm sure you've heard the title track... but that album is a fucking classic. Actually, I take what I said about Defenders of the Faith... Painkiller is 100% my favourite Priest album.
They've got a few weak albums - I hate Turbo & the Nostradamus album. But other than that, their discography is remarkably solid. And some people really love Turbo. But even their latest release, Firepower is a very strong album.
I am so lucky that I've seen Judas Priest & Iron Maiden 3 times each (and for the first time ever, I saw both bands in the same year... like it's the fucking 80s). So if you like NWOBH bands... you definitely need to check out Priest, they're legends for a reason - I'm sure @tlr would agree!