Going back into recent history, the most distinctive feature of clergy dress was not the collar. It was the color black!
There are basically two types of collar: the tab-collar, which has a little strip of plastic that slides into the sides of the shirt collar; and the neckband collar, which is a long strip of plastic or starched fabric that attaches to the shirt with buttons at the front and back.
Neither type of collar is specifically "catholic". This bugged me when I first started wearing tab collars, and people would say, "but you're not Roman Catholic, you're Episcopalian! You should wear the neckband collar!" This is patent nonsense, my friends. Now, in England, where there is more factionalism between Evangelical and Anglo-catholic, it does serve as a subtle indicator of one's affiliations, but for you, don't worry about it.
What I have in my closet (everything purchased from Almy):
- 5 black short-sleeve tab-collar shirts
- 1 grey short-sleeve tab-collar shirt
- 1 grey long-sleeve neckband shirt
- 1 black short-sleeve neckband shirt
- 1 black long-sleeve neckband shirt
So everything is either black or grey. I don't believe that my clergy attire should scream "fashion-forward!" but "a priest of the church". You might disagree. That's fine.
I've got more tab-collar shirts, since that's what I tend to wear on weekdays. They're much more comfortable, and you can pop the tab out and undo the top button when you're driving somewhere. It's a blessing in the summer.
I wear the neckband shirts mostly on days when I know I'll be wearing a cassock. The reason is that the whole white circle of the neckband can be seen above the edge of the cassock, and then can be seen in its full height at the notch in the front of the cassock. This look (which I think is super-classy) has been replicated with special sorts of neckband collars called collarettes. See a photo here. If you buy a clergy shirt that's designed to have this look, it'll be called a tonsure shirt.