Brokkin - I'll speak from coming from the same area that you were. When I was over 400 pounds I started on a 12 year old Raleigh MTB with 32 spoke wheels that hadn't been trued in forever, and probably rode it a thousand miles before I broke a spoke. I replaced that bike with a Specialized Hardrock, a new one, that had 36 spoke wheels and I rode thousands of miles before the wheels fell apart - not due to weight, but due to improper brake maintenance.
I only started to have wheel problems when my power increased - greatly. When I was 380 pounds riding a Trek FX with average speeds of 16-20mph over 20-30 miles a day, I had wheel issues on 32 spoke cheap 700c's.
I replaced that bike with a Surly Long Haul Trucker that's got 10-15,000 (I don't track mileage directly anymore) miles under my big powerful torquey butt, and problems have ceased. *knock on wood*
I've got a friend with a Giant comfort bike with 32 spoke wheels who is well North of 400 pounds and rides it weekly. He's yet to have a wheel issue.
I do believe that wheels can be a weak link, but there's a ton of other factors to play. My experience, again, is the combination of weight and power that really starts to make it a problem. If you check for popped spokes every couple of days and replace/true/retension as needed - that's more important.
(back to the shadows..)