re: How much of an emergency fund do I really need?

1. Definitely contribute to your 401k. Its hard to get at the money, so it makes raiding it harder. and starting early helps your money grow.

2. You can use your roth as emergency savings. You can withdraw your cash without penalty assuming you don't touch gains.

3. I think its worthwhile to have a month or two of expenses in cash. Yeah, you don't earn interest (or much) but its better to tap that than get into the habit of digging into savings.

In your situation, I would (in this order)
a) Get $1000 in cash in a savings account, maybe $2k
b) Max out your roth each year
c) Max out your 401k
D) start a brokerage account on the side