Vanguards portfolio tester
Dont waste any time with this for the near future; the function is broken on their web site. They quite helpfully noted that they're aware of it and tech support will get to it sooner or later, but they wont commit to a date to repair it.
You can move money from one fund to another for analysis, but you cant add any new funds or you get a 'page not found on our web site' error and it prevents you from backing up and preserving the numbers you typed in.
I'm beginning to get a little concerned about the quality of vanguards web site. Early last week all my bank transfer information was replicated six times, only one of them still working (#5!), this week a portion of the site stops working, apparently whoever changed whatever didnt test the change, and they appear to be in no hurry to fix it. :P
Be fearful when others are greedy, and greedy when others are fearful. Just another form of "buy low, sell high" for those who have trouble with things. This rule is not universal. Do not buy a 1973 Pinto because everyone else is afraid of it.