Youre the only one who can answer that question. Do you have everything there that you want to monitor on one screen? I dont like tiny charts so have lots of monitors.
The number of monitors should be commensurate to your P&L. If you make less than $1-2K a day (gross) then you only need 2 monitors. Heavy hitters that trade different baskets of stocks need to keep track of different indices, hence the need for 3 or more monitors. Most daytraders really only need two 21" monitors. When I see traders with 7 or 8 monitors who make less than $1K a day, I just chuckle to myself. These extra monitors are more of a hindrance and cause trading paralysis because of the information overload.
Everyone has their own strategies and style of trading. Not everyone trades the same way. That's why some make money and some lose money. You might only just look at the ES to trade stocks but other use more technical factors. Judging traders by how many monitors is ridiculous. Sounds like you are just jealous. I personally only have 5 but having additional ones so that I don't have to switch pages would be useful.
If you can't make money with 2 monitors, then all the extra monitors won't help one bit. It's pretty much overkill.
I use 3. 2 for charts and market data and one for the trading platform. Don't really need more right now. Best Natalie (as for surfing the net and computer games etc. YAWN!)
I am with you Gordon. I use one monitor with 3 pages. I would go bannanas with more than that to watch. Though it is a good idea to have 2 separate computers. One for the orders and one for the charts. Especially if you do trades in minutes not hours.