If it helps i'm happy to have several positions open at once.
Day trades I can have up to 7/8 in nas stocks but this is the most ive had and usually 4/5.
Forex 3/4 but usually 2 at once depending on opportunities
Futures 1/2 as i dont look at that many now usually ftse and es
I think it depends on what & how you are trading. I used to only ever have one trade open at a time when i was specialising in the ibex and i felt this was more than enough, but then it was ranging over 200pts per day... ah that was the life