[Soultrader]

Personal preference I would say. I like the YM because of its movement and I find it easier to time entries. I like the spread of $5 a tick.

The ER2 is wild and tends to trends fairly well. More bang for the buck.

The ES is a little too jumpy for me. Also the top traders in the world trade this contract so the competition level is high. Also the spread is $12.50 a tick.

NQ's... now I have no idea.

You should pick a market that fits your trading style and personality. Although you may have a great methodology, you may be stuck in the wrong market. Play around... you'll find something that suits you.