Don't be tricked By the 0% down

Purchasing a house was a big step in our lives. My brother always cautioned me about buying a house because he felt his home purchase reduced his flexibility in life. It tied him to a particular location and required a decent amount of effort to move on once he was laid off. After owning a home for 1.5 years we most certainly agree. We need to stay here at least two years for tax purposes and even then if we decided to move we might break even. Bottom line, be prepared to stay put for a while and don't expect real estate prices to continue growing at the phenomenal rates that they have been. We love our home and we love the location so we lucked out that we are going to be here for a while.
Ok, with all the finance options floating around there are two options that I want to discuss in detail. In the past 5 years banks have been bending over backwards to provide ways for folks to purchase homes without the standard 20% down payment. There is a tremendous amount of marketing for 0% loans, 5%, 10%, and 15% loans. Basically banks offer you a typical mortgage combined with a Home Equity Line of Credit(HELOC) to handle the down payment. The mortgage is your ARM or 15 year or 30 year or interest only loan. The HELOC is a variable rate loan based on prime plus some percentage based on your credit score.
We opted to go with the 5% down plan because we didn't want to liquidate our stock holdings. Here is what we got:

$235,000 5 year arm at 5% Monthly payment around $1100, $1500 with taxes and other stuff
$50,000 HELOC intially at 5.75% Monthly payment around $235

Does anyone notice what is wrong with this picture? We didn't until after we started making payments... Tomorrow I will talk about the interest only loan and how I abhor the idea...