I have recently become addicted to knitting fingerless mittens, because they are such a wonderful garment for exploring textures and colours - small enough to take anywhere, and the finished object can be worn and admired easily (unlike socks, which tend to hide in shoes).
All the fingerless mittens/gloves are knit with fingering weight yarn. Unless otherwise specified, semi-solid and solid colours will yield the best result. Highly variegated yarns tend to obscure the pattern.