I was fortunate to find CrossBreed SuperTuck Deluxe early in my holster search, so I've avoided the "holster drawer" to which chuckusaret
alludes (thanks for your service, BTW). It works extremely well for me carrying a full-size XD-40 service.
The importance of a good gun belt, too, cannot be overstated. It must be stiff and resist twisting and sagging, and over time I've found the dedicated gun belts to outperform and outlast generic belts. You'll pay more for sure, but it's worth the extra money.
Here's what I recommend:
I understand the CrossBreed belt to be a good choice, too, but I personally haven't used theirs.