Tick chart for ES looks different than YM

[BlowFish]

The more important thing is the range of movement over the time frame your interested in. Volatility if you like.

In an ideal world you would want small tick size (granularity) large range and volatility within that range. Its easy to see why the ER was popular. Oh and or course you want thick volume traded so can you can get in or out easily (S&P certainly has that in spades). A higher $ value per tick can be good in so far as it helps keep commissions down (compared to amount traded). However if there is no volatility its tough making money. Still imo its better to have large $ swings with a lot of small ticks rather than large $ swings with a few big ticks. Worse is small $ swings with large tick size.

It's probably worth considering margin requirements too though personally that's seldom an issue for me as I tend to trade small compared to my account size. (Actually it needed considering if I required overnight DAX margin sometimes and foolishly IB used to count after 4.15 GMT overnight)

Looking at any of these parameters without consideration to how they all interrelate is not likely to yield wise decisions. Also dynamics change sometimes quite frequently and radically. The S&P for example is quite a different animal last I looked to when I traded it. In those days 20 or even 30 point runs where not unusual last I looked (some months back) 8 point daily ranges wherent uncommon. I would guess its enjoying a bit more volatility again now.

It's all important stuff (along with time frame you focus on) to get something that suits your own personality and risk tolerance.