In reply to Trangia:
Also had a good experience with Europcar, in Norway (OK, it wasn't cheap but nowt is there!)
Booked the smallest car ("Up! type") possible in Roros ("Frontier town" type of place), to get us back to our vehicle at the end of a 2 week canoeing trip. The franchise was basically a scruffy garage selling mostly skidoos down a back street. This was good because I was a scruffy canoeist who'd been carrying a canoe on my head for half the previous 10 days, and was worried they'd think I was a tramp. They couldn't have been more helpful. Europcar hadn't delivered the asked for car, which was apparently coming from Trondheim, 200km away). So they'd got their courtesy car, a large Mondeo Estate, ready for me. Slightly scruffy, with one hole that looked like someone had shot it, but otherwise perfect, and we could get all our baggage in rather than somebody have to sit with it for the 4 hours it took to fetch the van. On asking where I could fill up the tank on return, he just said "ah, don't bother". I was worried this was some sort of way to get me to pay extra on fuel but, no, they didn't use it often enough to need it filling up.
Less good experience with Hertz giving away our car after we arrived an hour late at Oslo once, apparently we should have phoned from 30000ft, but that's not for this thread and it got sorted eventually!
As an aside, I am trying to remember how many times when I've hired a car I've actually ended up with the type or size of car I booked. Always seem to end up with something entirely different (a Transit in the second case above!).