Croesus
Adventurer
Golem Tractors & Harvesters
UPS (United Portal Service)
International Exchange Markets
Methane Biodigestors
Gas-Burning Stoves
Street Lights
I see two problems with the above - cost and fragility.
How much would the typical stone golem cost? Can it improve agricultural productivity sufficiently to pay for itself in a reasonable period of time? Also, what about the farmers? Presumably those with golems would have a strong incentive to buy (or steal) as much farmland as possible, to get the most use out of their investment - where do all the small farmers go? Productivity improvements are valuable when you have relatively few people with relatively large expanses of land and resources. Reverse that situation and society will tend to find employment for people, even when such employment is not very productive.
Gas-burning stoves and the like sound good, but what happens when someone lobs a dispel magic or three? Unless you are proposing a fairly modern, peaceful society, it would be very easy for enemies to cripple an economy with a few targeted strikes against the infrastructure, or to spread terror with a few low-cost attacks in crowded areas. (Of course, this is a problem with having magic be ubiquitous in the first place - a 1st level wizard with a wand of fireballs could do a lot of damage in very little time. Add in a potion of invisibility, and he might not even be caught.)
Also, if magic is a limited resource, using something like ley lines, then a very effective device is a simple enchanged metal disk. The disk is crafted with a simple spell - spin as fast as possible. Once started, it continues to spin faster and faster until all magic within range of the disk is sucked dry. (Note, this idea is from some old Larry Niven stories, including the book The Magic Goes Away.)
I've always seen high-magic societies such as these as the perfect setup for a post-apocalyptic campaign. There was great magic in the Before Times, but then the cataclysm came and society fell and...