At the risk of sounding absurdly cheap...I have had some pretty good success with the likes of Dickies-brand workbelts from WalMart as well as a similar brand (the name escapes me at the moment) from Academy Sports and Outdoors. The most expensive of these was just under $20.
I work in a "corporate casual" office environment and use a brown belt of this type even for most of my non-gun-carrying wear. I've even worn them with dress slacks, sport coat, and tie and haven't stood out like a lightbulb.
These belts are right at the 1-1/2 inch mark and are quite sturdy...they help hang on to my full-size, steel-frame 1911 and two spare mags quite nicely...no sag, no movement, they keep everything nice and tight and in place.