New TV show: Combat-Wombat Makeover!
Until you get firmly ensconsed on a job where they don't care that you're a shooter, do not wear BDUs or 511s to work.
Don't shop at the gap, or old navy, or the latest trendshop... Think Orvis or LL-Bean for your casual stuff, and think simple, and not too colorful/this year's trend. This stuff will last you for YEARS, not weeks or months (I swear, I think some people view clothing as disposable "accessories.")
Buy your business attire at better stores. Brooks Brothers is stodgy. But it works. Take a look at their stuff. Then hit a bargain suit chain, and see what they've got that's like it. You DO NOT want the latest style and fashion here either. If it looks like it belongs on a franco-italian pimp, that's a bad thing. If you do this right, it'll last you for years.
For shirts, avoid the silly collar styles - they go out of style. You want what you could have seen 20, 40, 60 years ago... And a nice white patternless HEAVY cotton shirt will go with anything. Get real cotton, and learn how to use an iron. If you're doing business casual, Levi's Dockers rule.
Get two _good_ pairs of leather dress shoes. When you break a few hundred dollars down over 10 years (or more...), it doesn't seem that bad.
When you have the chance, pick up a simple tux and some inexpensive but nice black dress shoes (surplus will work for them...). It'll come in handy.
You have to LOOK the part to GET the part.