As a garden variety swing/momo trader, exposure to as many liquid markets as possible produces my best results. I am swing trading 48 futures contracts, with some Forex and Equities/ETF trades as well. My entries are based on chart patterns that do not occur very often - I avg 5-6 entries per week.
I don't trade these. If it is about equity index I use the ESTX50 (European Index). Besides that I use futures related to other categories, such as bonds, agriculture, volatility, forex, metals.