I enjoy Spotting, I dont always collect regs for some reason.
Only when there is something interesting such as the Trooping of the Colour Flypast I would like to know the aircraft involved.
I also collect the regs of the aircraft I have flown on just to keep as personal record. (The Excel spreadsheet sounds good, might try it).
I also Like trains, but a certain type of trains, STEAM!!
These Electric and Diesel Boxes on wheel dont appeal to me even though I drive them.
I also like Birdwatching, I like birds with long hair and a BIG CHEST