Depends on your use case. For desktop use, ubuntu is really good because of actual drivers.
If you want to use a stable linux distribution on a server, i can also recommend CentOS (open source RedHat Clone) or ubuntu LTS versions (long term support).
Another nice thing is, if your use case need that, to build your own linux from scratch.
I had good experience with twitter and facebook (if it is a B2C product) in the past. Press release is also important, but in the past most of related big internet sites ignored our press releases - I think you need to figure out who (responsibly person) to send your pr (e.g. at techcrunch, heise, TR etc...) to be not ignored. If you have a physical product a good way to promote it is to send it to related bloggers and internet sites to test your product.
I look at universities for design students (graduated). I had general good experiences with that way.
Another possibility might be to look in eastern europe for offshore design agencies.
As mentioned already, one possibility is to take part in events... For me personal, I've been looking within my network and business contacts. Services as linkedin or xing are worth to look at.
I can recommend the open source pendant http://piwik.org/. You can install and operate it on your own servers easily and all data is stored on your machines.
On the first view AWS services seem to be cheap. But be aware of additional costs, for traffic, requests (no, that is not in the traffic included, e.g. SOAP requests), IP addresses, persistent storage or snapshots for your servers (e.g. EBS).
Big advantage within the AWS services is that you can reduce your CAPEX and your invest in your own hardware infrastructure.
If you calculate your use case detailed, you will see that sometimes dedicated servers offers are still cheaper than some cloud hosting services.
nice pointer - thanks! I wondered myself, why google is not more focusing on further crowdsourcing services - with google baraza they might place another successful service on the market...
I want to mention at this point http://www.opscode.com and http://eucalyptus.com/ > they are both successful with open source (of course they are not anymore early stage startups)
I'm using S3, EC2 for mostly all test-servers, and some EC2 instances also for production modus (resources were allocated when we need them). But as already mentioned, you have to be aware of the costs - so, I combine AWS with dedicated hosted servers also, because it is still cheaper yet.
The best things within AWS-Services are from my point, that you save CAPEX for your own infrastructure and you're more flexible in scaling (if your architecture supports that). But keep in mind that AWS has some "hidden" costs you should be aware about (charge for requests, own IP-addresses etc..)
From my point it depends mostly on your role and your responsibility. If you're responsible for the architecture, design and concept, and beside you also other resources in your company are available - you're right, that you won't spend the most of the time for writing the code. From my personal experience I can say if you deal with IT-operations, even if you automate the processes (deployment, roll out of new servers etc.), there are still about 1-3 hours a day that I hack into the terminal/console to take care and improve my infrastructure.
If you want to use a stable linux distribution on a server, i can also recommend CentOS (open source RedHat Clone) or ubuntu LTS versions (long term support).
Another nice thing is, if your use case need that, to build your own linux from scratch.