Hi and welcome to the forum.
Personally I'd go for a low mileage 160, and I'm told the suspension on the late models is better than the early ones but as I'm a fan of the MGF I have no personal experience.
I wouldn't bother with a hardtop, I use my car all year round and nothing beats dropping the hood on a crisp morning.
There is a buying guide off site
here
with lots of other how to guides
here
.
However one of the greatest things about owning a MG is the community, weather you own a MGF, a ZS or a pre-war model you are part of the group.
James