Selmer MkVI Baritone.
We have a nice example of a Selmer MkVI baritone in for sale. It's one I worked on some years ago when it had a different owner. The instrument had a full overhaul and I'm pleased to see it is still playing well.(Though I have given it a service and done any minor tweaks necessary.)
These classic Selmers do seem to be a good investment. A few years ago Selmer baritones were half the price they are today. So the price now may seem a bit high but these instruments more than keep their value!
If you fancy a decent investment a Selmer MkVI seems liek a good bet. And you get a decent instrument to play with too.
See the saxophones section for more details.