Seeing as you're more experienced on the Windows stack (saw your C# posts), I'd suggest not dealing with NodeJS at all if your aim is to push out and maintain this project with less friction.

If you're thinking it'll scale, it's much better to deal with scaling problems in a stack you're familiar with. So for your server stack I'd suggest these:

- PaaS: AppHarbor or Azure Cloud Services. You can easily scale up with them by a few clicks.

- Server-side: Seeing as you chose NodeJS, I assume you're going to use the stack's asynchronous nature, might I suggest looking up SignalR (http://www.hanselman.com/blog/AsynchronousScalableWebApplica...)

- ORM Layer: NHibernate

- DB: MySQL

Again, I'm not saying not to use NodeJS because I'm some sort of Microsoft Fanboy, I'm just giving suggestions based on how much "better" you can push out your project "quicker", and maintain/support it with lesser friction.