I hire an architect to design and draw a set of residential plans from scratch based on my creative input and vision. I pay the architect for the plans. I build the house. Who owns the plans? The homeowner, the architect or it depends?

You are the customer and paying a fee for the plans. That is the product/good that you are buying. You should receive the PDFs and the DWG files as part of your deliverables.

So should the architect then be able to re-sell the same exact plan to another customer/builder without my consent?

I ran into same issue recently and the architects proposal said the plans are their property. I pressed them on this explaining that this first build is intended for my personal use but if i can build and flip for profit in the future for retirement income i might want to reuse some of the drawings . They said that was ok. I think what they particularly don't want is you selling just the plans as your work product/intellectual property. If it's your build they are okay even if your'e planning to sell the build . That's what I got out of it anyway but I won't do it without vetting it with a competent real estate lawyer.

With regard to what happened to your friend , I can see a volume builder being treated differently than an individual.

I'm curious about what the judgement against him was in terms of financial impact . Did he just have to pay for the plans again or was it more punitive than that?

My situation is a little different than the previous discussed scenarios. I'm not looking to use the plans to build again. In fact, quite the opposite. I assumed these plans would not be used by another builder/homeowner. I discovered the exact plans were used to build my exact house without my permission/consent. I paid a premium to have a set of custom plans created, starting with a blank canvas and my vision and ideas.

http://swamplot.com/urban-living-gets-29-million-penalty-for-copycatting-townhomes/2018-11-08/

Bingo

The architect owns the drawings and the IP.