Toy & Model Cars!
My mission is to collect at least one model of every car ever modelled! (And some lorries, buses, fire engines... too).
I think you will agree that I probably own far too many toy cars/lorries/etc. Between me and my brother, we have over 650 Matchbox sized toys and nearly 500 1:43/1:50 scale models. And a few other oddments too. I should probably point out that the collection has only doubled since we left school, no more than that. Yet.

These days, most of the older models that I pick up are from the Market/Autojumble section of the Great Dorset Steam Fayre, and similar places, although I do occasionally buy from shops. I haven't yet braved the internet sites, for fear of spending far too much! I have also recently started buying new Matchbox (and some of the less extreme Hot Wheels models) too, mainly thanks to getting some bargains with the demise of Woolworths.
We have, obviously, got a few more real bargains over the years. My favourite is the International Crane in Chipperfields Circus colours that I picked up from a School Christmas Bazaar for 10p when I was about 12. It's not in the best of condition, but they now retail for at least £20, more likely £30-40!

I have put a few pictures of some of my models to the right, sorry they're not great, but I'm still working out how to get the focus right on these close-up shots.