I tend to purchase a lot of MR2s, ASL Garaiyas, and 'vettes. Besides those main three, I also like to buy special paint jobs of certain cars, even if I'll never drive them.
In GT5 I tried to go cold Chaparral - but I seemed to buy alot of RX7's - SO many flavours. Heavy rotation.
When I got online and Cash fell from the sky like rain - I bought every JGTC and Nascar - which was silly as now it is a real pain to have to scroll through them to get to the other side of my garage when I look for something interesting to drive... I've only used one Nascar - and the JGTC/SuperGT I tend to use my ARTA NSX or Garaiya.
It hurts busting a junkie - But Jesus built my hotrod
The Caterham Fireblade. If I see one, I buy it ASAP
It's my dream car, and I want all of the colors.
Even thought I have 7 or 8, I only drive one of them, which is fully tuned with 257bhp and 450kg, and it is a rocket. Ohh, and it is Plum Purple Metallic. It really matches the car
Anything unique, classic, or just plain 'interesting'. Pretty much anything that catches my eye - like the '98 Ford Taurus SHO - I never knew that thing had a 2.3L V8 tucked under the hood until I read Wiki (and a few other places before y'all complain Wiki is unreliable).
Still can't get that friggin' Mitsubishi FTO Super Touring Car though, be wanting it for months...
Mazda 323F
Mazda Lantis Turbo R
Toyota SERA
Pretty much any Zonda.
Pretty much any Holden.
Pretty much any Race Car.
Pretty much anything excluding the PT Cruiser, 90% of the Skylines, MX-5's/Miata's/Roadsters, and the FGT.
I would consider buying 653 cars last month normal.
Upon checking I currently own 83 Zonda's. "Guys, I think I'm an addict."
Jensen Interceptors in all available colours. I saw one stop at the lights outside the curry house I was eating in last week. I went outside and tried pressing the purchase button. Unfortunately the driver was having none of it. It really is a beautiful car, especially close up.