Conurekid, be careful with Metal Halide based lighting.
I typically only specify it for exterior use. However, I have been forced to specify it for interior use at times. I am uncomfortable doing so for several reasons.
1. The lamps can explode unexpectedly. This is very rare, and not a problem in a parking lot. However, your carpet (or worse, your fid!) are not as burn resistant as concrete, when the 500 degree fragments come raining down.
2. If the coating gets scratched off of a MH lamp, excessive (read: retina damaging) levels of UV are emitted. I know, I know...nothing ever gets scratched with parrots around, right?

Worst thing is...the human eye doesn't see UV light...so you just continue to stare at the TV, unaware that your retinas are getting cooked.
Oh, and by the way...the 24,000 hour rating is usually for 12 hours per day. That would be 2,000 days. Since the thing that causes an HID lamp to deteriorate is when it is turned on and off, that basically means 2,000 days, whether you burn it for 30 minutes at a time or 12 hours at a time. I just don't want you thinking that lamp is going to last 50 years.
Just looking out for ya.