I'm 29, and just started a new job with an excellent mandatory retirement plan. I contribute 5.5 percent of my salary and my employer deposits an amount equal to 8.5 percent of my salary. I have a Roth IRA I've funded previously, but I've never really thought about how much I need--I've always just contributed the max when I can or let it ride otherwise.
Now, I'm at a point where I might buy a house a few years from now, and I need to know whether I should be saving up short term stuff for a downpayment or if I need to further fund long term investments for my retirement. How do I go about planning how much I need to have saved up by retirement?