Making your app look totally different and not conform to any UI standards is good presentation? If that was true, why wasn't X hailed as the greatest UI around with all the different widget sets out there people use. I find it really annoying that MS preaches about how Linux doesn't have a chance at the desktop because no 2 apps look the same (which isn't even true) but then their Office and VS teams go off and totally ignore all of MS' own UI standards at every release.
No offense but if I knew those people were going to judge my application on whether or not my toolbars were beveled, I wouldn't be working for them much longer. Obviously if the UI sucks to the point that the app isn't usable without weeks of training there's a problem, but if the program works find and the only fault they can find is that it looks too 'normal' and that's enough for them to stop development that's also a problem.
Sorry for the rant but I really do like the idea of UI guidelines and frankly I think Linux and OS X both have Windows beat in UI uniformity, which is pretty funny considering how much MS touts their guideliness.