I would go with a larger HDD inside the machine as opposed to using externals any day. You'll have faster and more efficient access to your information and you won't have the unnecessary cable mess. When I upgraded my 2009 iMac to a 3TB an was able to get rid of my externals, I was almost ecstatic.
I think you made good choices and would be more than happy to be able to afford the same machine right now. Enjoy it!
I have (3) 2TB drives plugged into my current computer. I'm tired of waiting for them to wake up, having strange firewire outages, etc. I just ordered my new iMac with the 3TB Fusion. May put a 3TB drive in one of the external boxes for backup and if 3TB isn't enough, I'll use one of the externals as overflow.
I wanted one so I bought it. No need to justify anything
This right here. As long as you can afford it, why should anyone else care? I get Macs because I enjoy using them. I looked into Hackintosh route and decided against it. I prefer to use the computer, not mess around with it. I can't wait for my new iMac and have no regrets about it.