I've been a dual boxer in every game I've ever played. I've always found it nice to have a tag along healer. in DAoC I did 4-5 boxing for powerleveling new toons quickly but beyond that I generally only played two. There is a lot of value in dual playing and its definately a great way to get started. If you do enjoy playing 2 and have the resources I would recoment 4 to 5 however. Being self sufficient is very satisfying. Regardless of your decision, have fun.