I been collecting them for years, however, just today actually, I came to a bit of a crossroad when it comes to my future plans to continue collecting them. I really enjoy player's guides as they represent an age before most people had the internet and if you wanted to know the best strategy to beat a specific part of a game than it was the strategy guide or nothing. I also enjoyed how many strategy guides including cool artwork, maps and spreadsheets to help the player really understand the game they were playing. On top of that they provide a quick, well organized source of most info regarding a specific game (typically).
Of course, we now live in an age where any game that sold relatively well or has a sizable fanbase has a million FAQs, walkthroughs, longplays, let's plays, and all kinds of other independently published guides available for free online. These free sources obviously vary in quality, but the vast number of them pretty much mean there will be at least one that will help you through a particularly difficult section of a game.
With all that said, nearly every player's guide has been made redundant by the internet and its vast amount of sources. The only benefit that player's guides, sometimes, provide is having all information for the game at your finger tips like an encyclopedia or thesaurus. There is also the artwork and maps, but at this point most of these are available online, especially the artwork. And this is where my dilemma about continuing to collect guides comes up, as well as wanting to keep most of my guides.
Even though I own many guides for many of the games I own, I feel like I use them once in a great while. I also don't look at them for fun as much as I should. I definitely haven't decided that I'm going to fire sale them off, but my decision to continue collecting them is certainly something I'm weighing right now. I have some pretty rare and valuable guides that could be used to buy some really awesome games....