I think its important to keep buying houses while they are affordable in your area. I live near Coastal Southern California, and nearly any and every home that was purchased in 2011 and 2012 went up 100K. We were lucky enough to get into high gear and buy as many as we could-- a total of 6 new rentals in the past 3 years.
I only wish I had been a bit more daring in the early days of scooping these up... some were bought with private money loans and some were bought with a cash out re-fi of our personal (formerly paid for) home. I had been committed to staying out of debt, but, that caution easily cost us a 300K in a rising market. There are 3 or 4 others that we wish we'd completed the purchase on. The markets will cycle, but there are only so many chances one gets to buy at the lows.
Our cash flow numbers aren't nearly as attractive as some of ya'll in lower priced areas. My magic formula is to pay off the loans in no more than 15 years. but, if they cash flow at all, we know we can bank on the tenants to pay them off and we will be rolling in the dough at retirement time.
For our 2011-2013 purchases, our numbers are:
SFR-pd 162K, now 275K, rented for $1450
SFR pd 187K, now 325K, rented for$ 1575
SFR pd 225, now 285K, rented for $1450 (this one needs a remodel)
2 on a Lot, pd 287K, now 500K, rented for $2700
Condo, pd 97K, now 110K, rented for $900 (owned only 6 months)
Vacant lot, pd 112, now 225, no income.
Debt tied to these properties is roughly $550K total.