I first started trading bitcoins a few months back. Unfortunately the bitcoins were in a online wallet, instawallet. Instawallet was hacked and shutdown in April and I filed a claim to get my bitcoins back. But I am still waiting for the payout from the claim. So my first experience was not that great.
I am now interested in Scrypt-coins and I am mining Casinocoin, Dogecoin and Lottocoin. I earned about 50 dollars last month with a hashrate of 550 kh/s, so not bad. In the future my attention will probably shift to the more energy-efficient (memory-intensive) coins, or coins which calculations have a dual purpose (such as searching for prime numbers).