Collecting of comics has been going on since comics came into existence. The most sought after of comics seems to be the Golden Age comics spanning from the late 30's to the mid 50's. As of late Silver Age comics (spanning from the late 50's until 1969) have really sky-rocketed in price giving the Golden Age comics a run for their money. With that in mind, one should look very hard at the value of Bronze Age comics-that is comics from the year 1970-1979. Titles such as New Gods, Spectacular Spider-Man and OMAC are just a few of the great titles to pop up during this era.
If you consider that at one time Amazing Spider-Man #1 selling for $50.00 was a big deal-look and see what it is going for today in an Overstreet Guide or Wizard. With that in mind, a Spectacular Spider-Man #1 may not ever be as rare as the original, it will still always increase in value over time. There are many other titles as well that will do the same. Dr. Strange started a new run in the 70's, as did Superman's team up title: "DC Comics Presents". These are some of the gems that are worth looking into for investing purposes as well as collecting.
The obscure titles of the 70's cannot be forgotten as well for good investments. Some of these titles were short lived and printed in smaller runs than more popular comics. Some of the great titles to look for are Tor by Joe Kubert, Starfire and Ragman. These titles are excellent reading, great art and were more victims of the rising inflation than anything. Money was tight in the mid 70's and comics were increasing by 20-30%. Companies such as DC and Marvel and even Charlton were pulling out reprint stories to keep production costs down and get creative on how to make money out of this art form.
Investing in comics is a lot of fun and can be rewarding. Don't forget that comics are first for reading and enjoying and the investing is just a benefit of the entertainment.