Although I'm too new to trading to offer a difinitive opinion vis-a-vis trading, I have spent the last 6 1/2 years running my own business which started with my working from home and ended up with working in an office. In my experience working from home is great providing one has the space, peace and quiet, and the understanding of those others who share the home. A lot of people say that working from home requires discipline and I completely agree. What they fail to mention is it doesn't just require your self-discipline but also discipline in those around you to not interrupt you during the working day. In other words you may understand when you are 'at work' but will others? If this going to be a problem then get an office.
On a different note, a major problem I had was that working from home turned me into a workaholic. This can lead to all sorts of medical, stress-related issues. The cure was very simple - don't work at home and don't bring work home.
As, and hopefully when, I start to make consistent profits then I will be seriously considering an office in order to maintain a healthy work / life balance.