I go through phases in primary and secondary hobbies.
Right now cars is at the front because my Satellite just got back from the paint shop.
I also have audio equipment including vintage.
Main showpiece is a 74 vintage Pioneer SX 727 and BIC Venturi speakers with an Empire 698 teak and glass turntable.
I also collect "single spin" CD players because sometimes you want to grab one and pop it in instead of sifting through a multi-level menu.
The oldest CD I have is a 1982 release of "The Tubes". I've not personally seen an older one.
I miss cassettes. Probably because I was pretty good at making them.
I got GREAT results on a Realistic deck using Maxell UDS II (not the more expensive UDXL II).
You can "fix" the issue described above by running slightly hot record levels (+3dB) in Dolby B/C on a chrome bias tape but then NOT using Dolby for playback.
Some BP"C" is not "crap". I have a bad *** Sony dual record adj level remote deck that's the same model I bought new in 1992, and a nearly matching Sony 120 WPC receiver. That system also has a Sony linear tracking TT and runs with Boston Acoustics bookshelfs and an 85W Yamaha 12" sub.
Most of this stuff is thrift store, so not terribly expensive.
Then there's musical instruments. Mostly guitars, but I do have a couple Ibanez SDGR basses, a vintage Ensoniq keyboard and a set of Simmons electronic drums I'm modifying to be double bass. A few years ago I went on a "collect them all" challenge spree to pick up as many iconic body styles as I could with the max price for each of $100. I got Epiphone Les Paul, SG and an oddball "goth" flying V.
The prize in this category is a bought new 1986 Charvel that has the lowest serial number currently on record.
My current main is a 2012 Schecter with a Floyd Rose trem that plays remarkably similar to the fairly unique Charvel.
I do have an HO railroad project. In fact I was so into that when I was looking for my house, that I bought one with a 19x15 den to use specifically for that. I'm currently "double decking" to expand the run and adding a staging yard (including building a helix). My time period is 1948 (steam and 1st gen diesel) and loosely based on the PRR in the area where I grew up in Southwestern Ohio. I've been buying "modern" locomotives for about 15 years, mostly used and at a significant price reduction. It's easy to spend $350 or more retail for ones with sound and a "network card". I install my own sound and DCC in units built before that was common place. That can be very "interesting" as the space to work in is quite small. I do have some brass as well, for some prototype units that have not been offered in modern plastic and/or probably will never be.
I used to into 1/25 scale cars and have quite a collection including promos and some resin (Mad Max falcon and 67 Belvedere wagon).
I haven't done anything in that realm for years but I did gather the pieces to build a replica of my 73 Satellite (and the aforementioned wagon) as well as my 2000 Dakota. I have mostly completed near replicas of my past 73 Duster and 86 T top turbo Daytona.
...and then there's the cats. We have a sizable crew here- all "rescues" directly off the streets, and we we care for a feral colony of about 25 in the neighborhood next to the place where my wife used to work. When we started there were over 40, they were mal-nourished and disease ridden. Literally dying in the streets. Now all but one have been spayed/neutered and vaccinated. We were scheduled to take care of that last one this week, but life got in the way. That particular cat is in the custody of the only residents of that area that give a damn about those animals, so we are in better shape than if it were running wild.
...and finally (OK, maybe) I seem to be collecting automotive shop equipment. My most recent purchase was a Coats rim clamp tire changer. It has already half paid for it's self. Before that was a balancer. It has paid for it's self already. I am currently on the lookout for a used, commercial quality 4 post alignment rack with sliding jacks. My target price is $2500, which is what a consumer/residential quality unit costs new without the tuntables and jacks. I know it can be found, just have to be patient.
Whew!