A very interesting watch is the Omega Speedmaster Mark Series. Omega also made some Seamaster variants, which are also interesting.
Its not as iconic as the legendary Speedmaster from 1957 onward, but given it's main era was the 70's, it does have an iconic look, case and dials, that make them appealing.
And the question is how will their value proceed from here?
My personal question about these watches is that they feature, for the most part the 1040/1041/1045 series of movements (but remember the Mark 2 had the legendary c.861). And even though they are part of the Omega-Lemania partnership of movements, it is commonly accepted that the 10xx series of Omega movements were the beginning of the end of their fabulous run of top-notch in-house movements.
All you have to do is compare any of their previous movements to the 10xx series (and beyond), and even visually you can see there is a difference.
But still, these early 10xx series movements were not *terrible* as far as performance go. They are COSC caliber movements in general (although not all were submitted for COSC certification), and the overall look of these watches is so cool (I for example, love the television screen Seamaster below), that at the right price, it may be enough to want to add to one's collection.
Here is also a great write up on all these watches that should help you decide for yourself :)