The ones that I have are: MAC 187, 109 and 217. That covers your face and eyes. It covers your foundation and eyeshadow basically, but you can use these for other purposes as well. And I think these are the three that you really "need".
Why I got it: It's their duo fibre stippling brush, it's goat hair and synthetic hair, it's meant for "lightweight application and blending powder." When I first seriously got into makeup in my early twenties, this brush was the bee's knees, it was it all that a bag of potato chips, it was the HG of everyone for foundation application. I feel like this has really changed now that everyone seems to be using a flat top brush (including myself) to apply foundation. I bought this brush during last year's MAC Friends and Family sale, that was last year or two years ago? can't recall. I got it for 25% off, so I could justify it. I bought so many dupes until I caved and realized that they didn't compare, don't make the same mistake, buy the real one the first time.
What I use it for: I used to use this for liquid foundation application and I still do, it's great for that, you stipple your foundation on lightly and blend it in. It will not give your face a cakey look, although it does take some time to do, hence why I steered away from this method quickly. However, it is also good for blush application, it is on the bigger side though, so you might want to use the 188, or a substitute brush for that one. If you have a big face, the 187 is great for blush application. I also use this brush for powder application and finishing powder on top. I think everyone needs this brush.
How much is it: This brush costs $50.50 on the MAC CDN website currently.
Why I got it: There was a craze for this brush on youtube at one point, everyone was using it for liquid foundation application as well. Although it is meant as a contouring brush. I think for MAC brushes, their face ones are really the ones you need to get, this brush cannot be duped at all, I haven't seen any company do it (except Sigma's version), since that dome feature is really what makes this brush.
What I use it for: This brush is good for liquid foundation application, as it really blends nicely because of it's circular shaped, and short, dense bristles. I have read people saying that this brush sheds on them and makes for a very messy application having to pick off black hairs off your face.. eww. Mine has not shed and I have had it for some time, have washed it obviously too. Has yours shed?
How much is it: $38.50 on the MAC CDN site.
Why I got it: It's the perfect eye blending brush, hands down. This was one of the first items that I got from MAC ever. My numbering is starting to rub off too. And again, not dupeable by any other brand. "This brush has fine, densely packed fibers that are arranged in an oval shape." It is super soft and will not scratch your eyes and applies and blends very neatly.
What I use it for: This brush makes for easy fast and easy blending of eye colour on your crease. Also, I use it for blending concealer under the eyes, perfect for that. The 224 would of been too long and big for me, but this one is perfect.
How much is it: $27.50 on the MAC CDN site.
MAC brushes I lust over: MAC 130, MAC 134, MAC 182, MAC 150.
What brushes do you own from MAC? Which ones are your favourite/least favourite? Must haves? Dupes?