Actually - I disagree with pretty much all but the first statement...Hey Tony you will not regret it. Best toy I have bought in ages. But for
heavens sake don't get a green one...Although if I was buying again
I would get an 1800cc as they are that little bit more peppy (except for
zorruno's one) and if I had the money a MKII (the non-pop up headlight
model) with air bags etc just for safety's sake.
(best toy) and obviously Gary my MX5 would kick your silvery undercar
flourescent lit MX5s butt...

this on Monday!)... anyway I digress...
If I bought again, I'd look for an early model. Probably a late 91*.
I'd go really cheap, and forget about any paintwork problems, high
mileage and roof. I'd make sure it is straight, no chassis damage and
roadworthy though.
I paid a premium back when I bought my car to get the 1.8L . From what I
know now, if I had bought a earlier model, I could have had a new paint
job (chosen a non-standard colour if I wanted) ~$2K, new roof ~$1k,
possibly picked another engine up (even a 1.8L) and had it
ported/polished etc, installed ~$2-3k, got some sway bars the size of
the ones I have now ~$200, shocks and other suspension components, and I
would have basically had a new car for not much more than the price I
paid for the 94, and some of the amount I've spent since. Of course you
can do all these things over time also if you don't have much to spend
straight up (except the roof maybe... if it leaks!)
My 94 is still the ideal model for me, and the 1.8 is a little nicer to
drive IMO just because the slight extra torque makes driving easier, but
my recommendation is that when you buy, don't overlook at the older
models, and the high mileage ones, and the peeling paint ones. Those
are the bargains at the moment as they are so cheap to fix and
personalise to your liking.
I do quite like the feel of the NB models to drive, so may think about
one of those one day, but they are still way overpriced compared to the
NAs for what you get in my opinion (except for that $12k one Nigel!?).
And I think if the safety aspect got to me I wouldn't be driving a small
low black convertible...
And forget what people tell you about colour, style etc. Try out a few,
talk to lots of enthusiasts, and get the one you like. Then change it
until you like it more (even put lights under it if you like, or paint
it silver!). I happen to like the BRG & tan - it is a piece of LTD MX5
history. I like the black with black interior better - but obviously
that is just my opinion.
Good luck in your hunting, and as Kate said, go to a local club event or
get together before you buy if you can as you'll get lots more opinions
and help choosing.
Cheers
zorruno
* A later 91 means there is no need to worry about the possible short
nose crank problems of the very early engine, but this is easily solved
with a reconditioned engine for a couple of grand, if the car is cheap
enough to begin with.