My current interests are, in order of preference:
US WW II ships in 1/700 and 1/350, though the smaller scale is getting tough to handle as the eyes age (along with everything else);
aircraft '30's to '50's, mostly but not exclusively US, in 1/72 and 1/48 (I really like some of the 1/32 and 1/24 stuff that's available, but space is a problem, which is why I gave up on dioramas as well);
racing cars in 1/24.
My favorite build to date is a 1/700 resin USS Wasp, my first resin kit.
I have been but am not now a member of IPMS.
I'm what you call a "spurt builder" - hot and heavy for a time, then nothing for a while, then back at it again.
I began modeling back when an airplane model kit consisted of a block of balsa wood for the fuselage and a couple of printed sheets of balsa for the rest, all for 10 cents - no decals, no plastic canopies - and I got pretty good at it.
Tried a few balsa/tissue paper flying models too, but they always crashed and burned (who knew from weights and balances).
I do a lot of reading about 20th century naval history, thanks to Samuel Eliot Morison's 15 volume series on the USN in WW II which got me going on the subject a number of years ago.
I'm a rare former Marine who actually enjoyed life aboard ship, as long as I could walk and not fly aboard.