I just got hired on to be a developer (.Net) at an organization which uses a lot of smoke screens to make themselves look big and formal like IBM. On day one they set me up with a Win 7 machine and visual studio 2012. They also mandate suit and tie (first developer position I've been in that mandates developers work in a suit). I'm not feeling their culture or haphazard scramble to get me a dev machine using an OS no longer supported by Microsoft. Would it be poor judgement to tell my recruiter I'm not feeling this position or their culture?
You've uncovered the reason why contract-to-perm exists.
Of course, resign. If eHarmony matched you with someone that you knew on the first date that you would never marry, would you keep dating her?
Thank them for the opportunity and try to leave as nicely as you can. When asked, I would just tell them that the suit and tie culture really isn't a fit for you and you realized after a week that you didn't want to waste their time or yours.
I'm puzzled that you didn't seem to be aware of the dress code beforehand, at least during the interviews. It's always a good idea to pay attention to how everyone else is dressed during the interview.
I would additionally prepare some questions ahead of time to ask during the interview. Among them I would ask about the dress code (or work environment) as well as about what kind of equipment you'd be working on. It's not snobbish to ask the latter one because it will also give you an indication of how important they see your position, something that you may have discovered after the fact.
The important thing here is to not burn bridges and leave as politely as you can. If you used a recruiter, make sure he/she also knows how sorry you are that it isn't work and stress that you're doing it not just for you, but so that you don't lead them on and milk them for wages.
In short, use this as a learning experience. Take note of what makes you want to not stay and then put that on your interview list so this doesn't happen again.
If all the signs you see are rubbing you the wrong way in this new position and you can live without a paycheck for a while, I don't see any reason why you should stick around. Obviously, this place is not for you. If you drag it out, you will be miserable. Your output will most likely suffer. As a result, they might let you go with no chance to get a good reference from them. So, leaving in your own terms seems to be a better approach at this time.
Just my opinion. You and only you can decide what is best for you. No one else.
Since nothing serves so well as a bad example.....
I stayed with a company long after I should have left. They literally went to war with me, doing everything they could to make me quit(They didn't want to pay unemployment.) They set me up with a PIP which was so unrealistic as to be laughable. They did everything could to drive me crazy, right until I was carted out in an ambulance.
Don't be like I was. If it's a bad situation, get out. Worry about the rest later.
Gosh, why not try it for a while? Maybe you'll discover that suit-and-tie looks good on you. Maybe they've got a good reason for using that version of Windows. And, so on.
Basically, I would be very offended if, after hiring you, you "walked out on me after two weeks," just because "we ask you to dress nicely here," given that (presumably) "I've been doing that for years." I would feel very ill-used by you ... and that's a negative impression that I would not soon forget.
"You 'signed up.'" You accepted. Strive to blend in and to play-along, and keep your discontentment to yourself. (In other words, "be a professional.") If, after six months or more, it's still not working out for you, then start looking for another position.
Don't let yourself be seen as a "prima donna," nor as a "wallflower."
See this as a good opportunity for you to get to know yourself: why you don't see appropriate this position for you? Why you don't feel comfortable as a developer with suit and tie? And also, brainstorm about this company's strength or weaknesses you can see from inside: why they stick with Win 7? Why they ask developers to wear formal? Try to write down a couple of answers for each doubt you expressed in the original question, and the answer will come automatically. Together with some added value from this experience, whichever decision you might take.