I started with DogeCoin as my first cryptocoin.  I'm having fun mining various coins on my lowly ATI 7750 card (~140 kh/s).  So far I'm up to 0.3 BTC after mining DogeCoin, CatCoin, MoonCoin, and now CoinyeCoin.  I wish I could get into actual Bitcoin mining but the cost of entry is so high with returns that are so low.