Some great recommendations already, but a few thoughts:

• Victoria: O regem coeli; O sacrum convivum (à 6); Versa est luctum
• Peter Philips: Ascendit deus
• Allegri: Miserere (this unique recording from A Sei Voci specifically)
• John IV: Crux fidelis
• Lobo: Lamentations

N.B. Interpretation of this sort of music varies massively, so I recommend having a listen to lots of different recordings.

IMO, it was the Spanish, Portuguese and their colonies at the time that particularly nailed early sacred choral music. A good disc to start exploring their works is The Golden Age from The King's Singers (on YouTube here. For Victoria in particular, this disc is good.

For more Tallis, I'd recommend Heavenly Harmonies from Stile Antico. For his contemporaries, Treasures of Tudor England from The Sixteen has a good selection.

It's also worth delving into madrigals, the secular choral music of the time. Recommendations include:

• Thomas Morley: Now is the month of maying; April is in my mistress' face
• Weelkes: Sing we at pleasure
• Monteverdi: Sixth book of madrigals, especially Zefiro torna and Qui rise, o Tirsi; also, the other Zefiro torna

If you like that second Zefiro torna, search for the group L'Arpeggiata. They do some incredible stuff.

I'm going to be bold and say a few of the pieces above are quietly some of the best music ever written, but I'll let you explore yourself ;)