I favor yardage, that's the vast majority of what's in my stash.
Pre-cuts I view as a treat; I often buy them when I'm on vacation as souvenirs, mostly just to justify the extra expense. I tend to use pre-cuts with maybe one background/accent color fabric, so the pre-cuts get center stage. I do buy Hoffman Bali Strips a lot because I love the variety of batiks and in that case, it WOULD cost more to buy enough yardage to get that sort of variety and it'd take me forever to put together 40 different batiks that coordinate.
Fat quarters...I liked them a lot when I was a newbie quilter but now I pretty much regard them as scraps. Which isn't necessarily a bad thing since I love scrappy quilts...I'm just not motivated to buy them and I hate storing them - I usually toss them in the scrap bin, actually, unless it's really "special" fabric. The only FQ's I get these days are given to me or won in raffles at the guild.