Thanks all, it's given me some things to think about. A two seater open top car would be very nice indeed. However I usually have the kids with me at weekends so only having two seats would limit the amount of use I would get out of it. I suppose "fun weekend car" probably isn't quite the right description as I'm not really after a cateram for example. An on the basis of 2+2 that puts the MX5 out of consideration (if I was in the market for a 2 seater soft top then I would definitely have that on the list of possibilities). It's more about a good car that won't depreciate too much, something reasonably practical, reasonably quick, and a 2+2 coupe.
The fiat is an interesting suggestion. I've had a mk2 16v GTI in the past (loved it) so that's another one to consider. However I think I'd find it a little slow nowadays.
I've driven quite a few Corrado VR6's (and owned a Golf VR6) and agree with an induction kit it sounded like the clouds above had opened. Lovely sound. I've done a lot of research into Corrado's in the past so know the pitfalls with them (sunroof, heater matrix, timing chains, etc).
944 and 325i E30 are possibles too.
Once again, thanks for your thoughts. I knew the TT wouldn't go down well on here

The only reason I sold them in the past was that I had one a month and swapped it for a better TT and then sold that a year later when I moved house, didn't have anywhere to park it, and wasn't using a car at all (also with kids on way). Loved it at the time.