It is hard to know where to begin. There is so much out there. When I first got into Renaissance music (around 1990), I bought whatever I could find because there wasn't a lot around. From about the mid-1990's, availability became a lot better and many excellent new recordings appeared. You would probably do well following the recommendations others have given here. I'll add a few more.
The Naxos early music series, which has been mentioned, is a good inexpensive way to explore Renaissance music; there are a number of good releases out there. I haven't seen many of them in stores, but they are easy to get on the web. Check out sound samples and see what you like.
Also, I have thought of a particular CD that I find to be a great example of late Renaissance/early Baroque vocal music. Praetorius: Polyhymnia Caduceatrix & Panegyrica. La Capella Ducale; Musica Fiata. This CD is out of print, but used copies usually seem to be available. The music is gorgeous, and the performance is great. I can't figure out why this is out of print. Amazon has sound samples if you want to check it out. If this one is a pain to get, other CDs of the vocal music of Praetorius are certainly worth checking out.
If you check this out and like the style, you might also want to look for music by Giovanni Gabrieli; his music is richly complex and beautiful.
If you want to check out Renaissance/early Baroque music of a more folksy style, there is a lot of music from the British Isles that is enjoyable. One of my favorite groups that performs this style is the Baltimore Consort; they released a number of CDs for Dorian in the 1990's. This is the popular music of the day; it is fairly straightforward, and a lot of fun. Since Dorian went under, a lot of their CDs are now out of print, but used copies are readily available. Some are still in print; it seems that someone is trying to resurrect the Dorian label, so hopefully their many excellent early music CDs will return to the marketplace. Incidentally, while I was looking, I discovered CDs by the Baltimore Consort that I don't have yet, including a new one that just came out. I might just have to order them.