In my current position as a systems administrator for a financial holding company, I've been enjoying the fact I get over time for the first time in quite a while. My last two places of employment, I started out on hourly, and shortly after I was hired the whole department was changed to salary (no OT). One was private sector and one was public sector. Oddly enough, right before I was hired at my current place of employment, the IT staff had just gone the reverse transition due to an employee successfully arguing that we didn't qualify as exempt.
Most weeks, I put in 5 or less hours of overtime depending on the current load. However, when we acquire new banks or have a major project (like the Novell to AD transition), it's very easy for everyone involved to put in 20-30 hours extra per week. Of course, you will always have employees that will take advantage of this, but myself and others that still have a work ethic appreciate being actually paid for our extra time and give our best effort possible.
Now they are discussing transitioning back to salary due to the arrival of a new boss this year. I know if this happens they are going to lose a lot of experienced staff. This might be okay from a business financial perspective. In other words, hire less experienced staff for less pay on salary and it doesn't matter how long it takes. However, in the real world, you're going to upset a lot of clients that way when they're used to things getting done quickly and dedicated (fairly compensated) employees that are willing to work the distance with the customer and actually know what they're doing.
Rambling post aside, yes, OT is a good thing if you want good employees (for the most part).