Affinity and exclusivity are more important than raw specs if you're a wealthy car collector. That said, only two of the cars on my list would be on a car collector's checklist. I wouldn't let my cars sit, btw. I believe cars should be driven. That would make owning even 5 dream cars a tricky proposition. 3 would be more realistic. I tried to find pictures of the cars in the color schemes I would want them to have.
1994 Skyline GT-R V.Spec II- I fell in love with this car on my mission in Japan. It's not the fastest anymore, but is competent. I would only get it in gunmetal gray.
Mercedes SLS AMG Black- Stunning retro styling with supreme GT performance. Srey want.
Completely built FJ40- Not as a showpiece, but as a legitimate rock crawler.
Singer Porsche- This would be the car that would be in the special glass room that nobody is allowed into.
Daily Driver- Probably a new Land Cruiser or Tahoe or G Wagon.