hard one... maybe flying, dragon, steel, fire, water, and ghost. reasons:
flying: ive always liked flying types for being cool and birds are awesome
dragon: they have good resistances, most dragons have great stats, and that they know a variety of moves besides dragon
steel: steel, like dragon, has good defense and good resistances, Magnezone and others have levitate, which gets rid of ground attacks, and some steel types can be fast and can hit hard
fire: Fire types sometimes have great special attack or attack which is what i use the most
water: i like water types because they have some good stats and squirtle was my first starter. oh and, i liek mudkipz
ghost; well whats not too like about them? theyre cool! But sometimes theyre not that great battle wise
overall id say around the steel dragon flying types.