Bit too general I think -- depends on what scale and era you're into, no?
I'm a WWII buff first, and focus on U.S. birds first... so if I were talking to someone with similar tastes that was just starting out, I'd probably say focus on one theater of operations first, such as the ETO and start with the heavy-lifters -- the most widely used aircraft:
(I also would probably recommend sticking to one scale, and 1:72 does have the most options...)
1. A P-51D -- I would choose any GMP model, first, then Dragon in 1:72 (BBD or Glamorous Glen) ...
2. P-38 -- Any of the new Corgi's, I like Old's ..
3. P-47 -- any of Dragon's will do ..
4. B-17 -- Corgi's Memphis Belle -- doesn't get more iconic than that...
5. B-24 -- I like the SB or Pistol Packin' Mama the best... (have all these myself except for the PPM)
Then of course you'd need to start a PTO collection: a P-40, Wildcat, Hellcat, B-25...
Then you don't want to forget our RAF friends... spit/hurri/mossie/lanc...
Then you need some opposition... 109 (corgi's hartman if you can have just one), 190, 110... etc. etc.
Then how about the smaller theaters.. MTO? Or the Eastern Front... ?
Then what about the Jet Age?
Five, no sorry, can't really do it
