We have invested in OKC (single family) for 10 years. It has been a solid, solid market. We didn't suffer much from this last boom/bust cycle so prices didn't have as far to go down when it occurred. Oklahoma is a boom and bust town due to the heavy reliance on energy and lately, it's been boom. The town suffered mightily from the late 80's S&L meltdown that resulted in the Resolution trust purchases and it's sort of sick/funny to see the same properties in foreclosure. Right now, pretty much since the first of January, properties are selling like hot cakes with multiple bids and even some over-list offers (I've done it myself). For the last couple of weeks, every property I look at has someone else cruising it. Nonetheless, we are a relatively low cost housing market overall. Only you can decide how you feel about the long distance aspect.
Now... in the interest of full disclosure, and you can laugh if you want. I first heard of the "2% rule" at my first REIA meeting three weeks ago. We just do the math, and if they cash flow, we buy 'em.