A few years ago, after reading everything in the Hainish Cycle, I decided I'd try and get the whole thing in print. I'm not a serious collector, not necessarily after first editions or otherwise rare editions; but I did want hard covers, and I wanted editions that had dust jackets with all that funky scifi art of the 60's/70's/80's. So far the Hainish books have been good to me in the sense that none of it has been really rare and it's mostly under the 100 usd/eur point as long as you're not looking for signed stuff.
Unfortunately it gets a little weird with The Word for World Is Forest: The only good looking hard cover happens to be on one of the earlier editions and while I doubt it's truly rare, it's rare enough people start asking a lot for it. I finally got lucky and some kind bookshop on ebay put it up for less than 100, dust jacket and all, and I finally get to add it to the shelf.
It's not my favorite of the Hainish Cycle, but it's an easy recommend (I recommend everything and anything from Le Guin). I know it's a favorite for a lot of folks. Anyways, if you're just getting into collecting print scifi, bookfinder.com is fantastic for what it is (aggregator for the inventories of the big used book operations), and I guess every once in a while ebay can work out.
I just finished reading The Eye of the Heron for the first time. To me it had a very similar feel, and in the back of my head I was thinking how you could totally headcanon your way into saying this could be another tale from Earth's first (mis)steps into the cosmos and Hainish universe.