Before I bought my rental I had a similar question. I hate this answer but I have to give it here: "It depends."
For me, I was saving for a down payment and the I had to get a new car so I focused for awhile on cutting down the car loan amount. I'd say it was maybe 80/20 (car/down payment savings). But now it's probably closer to 50/50 because I'm far enough ahead on car payments that I'm fine as long as I keep paying the minimum. If it's credit cards on the other hand, pay that sucker off pronto. It does depend on the type of debt you have. Credit cards, student loans. Get rid of them. Car...up to you how quick you want to get rid of it. I'm saving for a second place now so I'm down to about 75/25. But once I pay off my car I'll rip and roar to save all for the house.
So it really depends on how comfortable you are with having the debt and if you're confident you can manage it well. If you're okay with it, then by all means save for the house once you get that bad debt out of the way. Otherwise, if the idea of debt keeps you up at night, then get rid of it all then focus entirely on saving for the investment.
Best of luck to you!