(1) Best for oily/combination skin when making your face cleanser: jojoba (most like skin's own natural oils) and grape seed oil. Grapeseed is great if you're on a budget because it's inexpensive and easy to find.
(2)Best for evening out skin tone: rose hip seed oil. I actually use this all by itself. I just put a few drops on my fingertips and tap it onto my face. I also use it under my eyes.
(3) Best for anti-aging: Argan oil. You only need a little! This stuff is RICH. I actually can't use it on my face unless I'm sunburned, in which case it's super healing and my skin just drinks it up. On "normal" days, though, it's too heavy for my face. I like it and coconut oil for body moisturizing, though.
(4) Best for eczema and skin irritations: Black Currant Oil. This one is hard to find so you may have to get it from the vitamin section in capsule form and then just break the capsules to get the oil out, but it'll be more than enough. This stuff is grand after a day of hiking when your legs are all irritated from the brush you've been through.