Buying an investment property!!!

Hey,
I've got a question I can use some help with; I am still doubtful of which is the more suitable option for my circumstance. I have a full-time job now and plan to get into real estate full-time later. The residential property I am living in is mortgage free. However, I am considering buying a condo that I would rent out momentarily and then move into once I sell my home in about seven to six years.
I have a few savings, which is enough to settle the 20% down payment. Only will need to bankroll the rest of the purchase for the condo.
As it's an investment property, I thought getting an investment property mortgage; I guess I can write off the interest on my tax return unheeding of whether I choose a HELOC or a mortgage.
I'm pretty much delighted in hearing from those of you who might have had a similar situation, and what you had ended up settling.

I have been a landlord a number of times and would never do it again. Finding tenants is easy but finding good ones can be tough. I could tell you a lot of horror stories about my experiences. Typically mortgages are a little more difficult for a property you are not going to live in.