Clarks desert boots are really casual. I'm sure they're fine for where you work but it's like the smallest incremental step up from sneakers that exists. They wouldn't be a bad pickup as they're pretty timeless, kinda like boat shoes, but I'd be inclined to go a bit nicer.
If you're ok with buying slightly used then I'd go to an AE store, get fitted, try on a few pairs, figure out your size and width, then buy something off ebay. $80 on ebay can get you a pair of slightly used $350 shoes if you hunt a little. And I'm not really slobbering AE or anything, just that they have stores everywhere so figuring out your ideal size is not a big commitment.
Unrelated, has anyone heard of Centre Commercial? I'm liking these:
http://www.eastdane.com/pantal-suede...&colorId=11841