My favorite reggae is roots and dub from the 70s. In no particular order, here are some of my absolute favorite reggae records, and I highly recommend all of them.
Burning Spear - "Marcus Garvey"
Augustus Pablo - "East of the River Nile"
The Upsetters - "Super Ape"
Culture - "Two Sevens Clash"
Lee "Scratch" Perry - "Roast Fish, Collie Weed & Cornbread"
The Congos - "Heart of the Congos"
Max Romeo & The Upsetters - "War ina Babylon"
Yellowman - "Mister Yellowman" (early dancehall stuff)
The Abyssinians - "Satta Massagana"
Hugh Mundell - "Africa Must Be Free by 1983"
Scientist - "Scientist Rids the World of the Curse of the Evil Vampires"
Check out some Barrington Levy and Tenor Saw records too. They were both more singles than albums artists, and the tracklists on his albums tend to have a lot of duplicate tracks. They're both dope as hell. You've probably heard Tenor Saw's "Ring the Alarm" before. It's his take on the classic "Sleng Teng" dancehall riddim.
Also, this is quite a bit newer, but a group called the Easy Star All-Stars put out a full album dub cover of Pink Floyd's "Dark Side of the Moon" called "Dub Side of the Moon". It's way better than it has any right to be, and I recommend that as well.
Madlib's "420 Chalice All-Stars" mix is 80 minutes of top-notch reggae in a lot of different styles. It's a nice survey.
This is only scratching the surface of reggae, but I think this gives you a lot of good starting points.