One of the first Orthodox CDs I owned is "Attend, O Heaven: Orthodox Hymns of the Great Lent and Pascha" by the choir of St. Seraphim Church (OCA) in Santa Rosa, CA. Blew me away! And if you're in an OCA parish, it will help you to learn how to sing "The Angel Cried" and "Let God Arise" (the Paschal verses). Has lots of hymns I've not seen others record, at least not on English-language CDs. "By the Waters of Babylon" just stops you in your tracks. I consider this to be the best Lenten CD I've ever heard.
I miss the good people of St. Seraphim...it was the local OCA parish (about 15 minutes from home) before I moved to New Mexico about 2 months ago. I heartily recommend
this CD. It's heavenly. If memory serves, they've done another one; I can't remember what it's called, but I vaguely remember seeing it for sale at the last one of their Glendi festivals I attended before moving (which I highly recommend attending, if you're ever in area; eat Greek, Levantine, and Ethiopian food, do some Greek folk dancing, and then head up the road a ways to see the historic Russian settlement of Fort Ross...
Something related to the topic, you say? Fine, fine. Since others have covered pretty well the Slavic and related chant, why not try some Arabic? One of my absolute favorites is the dear departed Metropolitan of Tripoli, Lebanon, Elias Korban (Qurban, if you're a stickler for transliteration), who did at least one amazing album of Byzantine chant in 1977 (it's just called "Divine Byzantine Chant", I think). I don't know if it's been reissued on CD or what, but copies of it show up on E-bay fairly regularly for $8-$12, if you have the appropriate equipment to play LPs. Check it out:Enna el-Baraya
Byzantine Arabic chant on CD is taken care of pretty well by the Choir of Balamand Monastery
(Lebanon), who have several CDs out (I have the one for the feast of St. John Damascene; it's great!), or the School of Ecclesiastical Music of Mt. Lebanon
(particularly their later CDs).
And while it's not part of the Eastern Orthodox tradition that you're probably looking for, I would be negligent in posting music recommendations without at least linking to the incredibly powerful voice of my favorite Coptic Orthodox "mo'alim", the one and only Gad Lewis:Shere Ne Maria
(A Coptic hymn praising St. Mary, St. Rafael, St. Mark, etc.)