Short sentences to communicate your mission/purpose. Spartan designs that focus on diving in and easing the call to action as much as possible. Big fonts, soft gradients. These are the tools of the 'pre-fab' layout.

When you're starting out, I firmly believe that you should ship first, and more importantly, that you only have, at best, a 'good idea' of how users are going to interact with your application.

As you get more users and get more feedback, then your UI/UX needs to evolve to meet with common use cases, or to cover use cases you hadn't thought of, or to keep up with demand. I strongly believe that you can't predict this going in, unless you have already built a very similar product for a very similar demographic, or unless you already have existing users.

You're 100% right in that the pre-fab design ideals don't leave much room for branding, but there definitely IS room for branding. Of the sites using these common design patterns, there are definitely ones that stick out moreso than others, due to superior branding. You can use the space that's left to reinforce brand without beating somebody over the head with it, and more importantly, without breaking ease of use.

In my humble opinion, THAT is the real challenge.

I also think that some of this design habits also point in the wrong direction. Just to explain better, I'd say that Drew Wilson is iconic of this. He's quite popular, and you can see some of his work here: http://dribbble.com/drewwilson/ He uses a mac-like style for web applications, and I think this is a huge mistake. Try to visit http://builditwith.me/: it's surely beautiful, but do you think it's 'usable'? I think it's not. But the most, I think it has no distinctiveness. Here there's another mistake: distinctiveness does not mean originality. My examples where websites like mint.com or posterous, or even Dropbox. These website can't be called that original, but they surely have a distinctive design, made of key and recognizable colors, way to use (or not) gradients, etc.

In my humble opinion, any design must obviously respect some key principles, like effectiveness or usability. But I also think that any design should point on 'identity', especially when building a web app, something most designers don't seem to care about.

On the other side, I think it's a very different problem, and I'd advise to not mix things up: there's style, there's identity, there are UI canons.

Bultwithme for example mixes web+mac UI canons, has a mac style and doesn't work a lot on identity.

Take Nike.com to have another example. It uses a web style, a bit toward the app format, with UI canons that are almost everywhere app-like... but it has a very strong identity.

On the other side, take Lightroom. It's obviously an app and uses desktop UI canon... but it has a definite identity that you can't mix up with anything else.

Also dropbox, as you cited, uses a quite standard web style and web UI canon, but it has a strong identity.

Don't reduce the identity to the UI canons or interaction styles: they are very different things. ;)

Branding is NOT about distinctiveness in visual design. Branding is about owning a particular position in the users' mind. ie. "The cheapest" (Wallmart). Or "the original" (Coca Cola). Or "Search" (Google). Or "Classifieds" (Craigslist).

The purpose of visual design, particularly on the web, is to communicate well and make your site easy to use. I don't believe it is to "stand out", although that can be a nice-to-have.

If you want to study the relation between visual design and branding, study Craigslist, eBay, Google, Apple, Amazon etc. Dropbox too.

On the web, the reason why most sites look the same is that we've found again and again that usability trumps "looks", since the browser is so limited. So sites have converged on a whole bunch of conventions. (I'm talking about the ux side of design).

Having said all that, I think it's totally ok to not follow the pack in terms of gradients and dropshadows etc.

Think about your potential user Joe, when he first hits your home page, with distinctive UI.

Will he think 'Oh... this looks cool! Let me mess with this, even though I'm not really sure how this is going to work' ?

Probably not, unless you have a really compelling value proposition to offer that would be instantly obvious to him. If your site does have such characteristics, go ahead and 'roll your own', by all means.

Otherwise, I'd suggest you go with a commonly prevailing/understood/acceptable design/UI to begin with, as it should facilitate higher rates of user acquisition (i.e. conversion) in relatively shorter time-frames.

There's nothing to stop you from re-branding (gently, gradually?) once you have achieved critical mass or a sizeable user base.

HTH

[Not really a designer here, but someone (who likes to think of myself as) having a good eye for designs/branding and UI engineering, with a good bit of experience at getting such things done.]

"Don't try to be original. Just try to be good."

http://www.logodesignlove.com/paul-rand-video

Design (especially UI) is an exercise in solving problems and designers often arrive at similar solutions. That's OK. What matters is whether the user gets what s/he needs, not whether the UI is memorable. Indeed, the less computer administrative debris, the better. I design for a living and the best success I've had is when the UI gets out of the way of the content and task.

There's even a style of writing on web sites now, especially startups. Very direct with short bold sentences. "BubbleDrubber connects YOU with Bubbles you Drub. None of the Flub!"

I think you should be more distinctive than that wherever you can. There are different kinds of nice that you just haven't thought of yet.