I must say I am registered at the OVI store but haven't used it once. If buying something would be necessary I wouldn't be put off to do this via the developer's homepage/paypal.

50€ for a mere entry sounds crazy, but I don't know what an entry entails behind the scenes.

I think the biggest benefit to ovi store or similar app stores is the payment processing, that's the most difficult thing to supply on your own. Especially if you have a global audience, want to take payment via SMS, etc.

A small game. Shisen-Sho clone.
I had few projects targeted at Ovi and this was the first ready to release. And I hit the wall. Badly.

I wouldn't bother with OVi store, even if you managed to get it in (so to speak), many can't get it out because of restrictions, bugs, etc. I can't buy anything from them for example. They have prices in RON and a listing for Romania but only take full Visa which is probably available to 5 people in the form they want (compatible with US-type Visa, unlocked for internet, secured). We use Electron here in 99% of cases, credit or debit.

After weeks of searching for an answer, I am thoroughly convinced it's not worth it and that, as a developer, one must seek other paths. Either a different store, that sells generic software and has decent payment, or a personal endeavor, like an international garage sale site that ends in bay and accept payment via a gold Paypal account (or what's it called).

The software I sold in my life was through a site that has since kind of changed, but it was a generic site and I liked them because you could upload an exe that self-extracts (or any other packaging method, one file only) and a predefined XML that contained all details. Also provided, free, a wizard-like tool that allowed for easy XML building.

I think it was the virtual software store. (The Virtual Software Store accepts Debit, Credit or Purchase Cards with a Visa, Mastercard, American Express or Discover Card Logo from anywhere in the world). No PayPal.

There are others. Don't give up. Aside from the fact that you'll deprive this community of a good chunk of its developers (you're it), doing this successfully will open a path for others.

And finally, there's always the option to make software unlockable by key (I like my RSA implementation) and personally accept orders via PayPal, and deliver keys based on email that made the payment.

You don't have to make it uncrackable, just hard enough to make it not worth the trouble.

The promise of Ovi Store is that it has a preinstalled link on every N900 and is heavily marketed by Nokia.
No other store has so good penetration, thus require a lot of effort for marketing. And even then I wouldn't count on high revenue stream.
Selling on my own is even worse. I have a lot to take care of and do not really want to take third full-time job in marketing and sales.

I would argue the point, apple is on every phone they produce, ovi store is heavily dependent on your phone model and for most of their low range candy bar phones isn't present.

Problem for the N900 is no one develops to sell, which I think is down to the process of getting things through their approval process and valuing the cost and time against the returns for all that effort.

I am sure symbian apps which are much more common would have a bigger following and more likely turn around.

I still think app stores like android and apple are bigger and have more penetration, mainly due to the fact everyone of the phones of that brand links to the app store from birth, is designed for that app store. OVI store isn't yet complete (still beta) and came after most phones were out, so the interface is a cobbled together mess to suit the differing OS and phone layouts that Nokia insist is a good thing.

Nokia are their own worst enemy and if they can't decide on an OS and a phone layout, how can a developer?

which ones come without the link to the ovi store pre-configured? the last low-end S40-phones i saw all had it.

the reason why it doesn't have much of an impact may be that people who buy a, say, 3720 don't use it for accessing the web... therefore, they don't have a data plan... and they never bother to set up the ovi suite or do anything else that would enable them to download software to their phones. a phones that's not "connected" doesn't make a good client for an app store.

Well you can release it on your own site if you want taking payPal?
I hope there is a game "NINJA FRUIT" like on the N900.

Ok. But we are talking about N900.
Apple App Store has 0% penetration in Maemo market.

Maybe you should reread: