I've made a lot of projects over the years but can't really pick a "favorite" one. Do you have that problem too? Is it easier to pick a favorite yarn over project? Favorite loom?
For me, if I had to pick a "favorite" loom it would be the All in One Loom from Authentic Knitting Board.
I prefer the gauge of this loom over the others. As for yarn, anything that is soft. I know that doesn't really narrow it down, does it? If I had to pick a project I would say maybe fingerless gloves. They can be finished within a day or two if I'm focused.