I have around 70 3.0 and 3.5 books, mostly WotC stuff but some 3rd party stuff. That's just D&D and d20 fantasy.
I also own every single M&M product ever released for 1e and 2e. I also own every single Spycraft 1e and 2.0 book ever released (including all the Shadowforce Archer books). I also own every single d20 SW book ever released by WotC including SW Saga.
All of that probably pushes my d20 collection close to 200 books, but obviously D&D is only a part of that. Probably around $5000 worth of stuff.
As far as other RPGs well let me tell you, I own a lot. I own an additional $4000 worth of old TSR 1e and 2e D&D stuff, almost every single FR boxed set ever released, every single Dark Sun product ever released, numerous hardbounds and Complete books, every Al-Qadim product, a lot of Planescape and SpellJammer, etc.
I own every WEG SW hardbound ever released. I have several Exalted 2e books. I own the entire WW Street Fighter line (out of print and very cool).
I own every HERO 5e book published prior to about June 2006 and a lot of HERO 4e books too. I have a lot of rare stuff too, like every Mekton Z book, the original Cyberpunk 2020 RPG, the aforementioned Street Fighter RPG, etc.
I used to own every Palladium book published up through the year 2000 (every RIFTS book, Robotech, TMNT, you name it). At the time it composed about a third of my collection. But I sold all the Palladium stuff. Strangely, those are the only books I have ever sold. I have kept everything else.
Even with all the Palladium stuff gone, I expect my collection would still add up to well over $20,000 worth of stuff collected over the past 20 years. All of my friends tell me they have never seen an RPG collection as vast as mine. And thats them just looking at the d20 stuff on my bookshelf. When I point to all the boxes of old stuff sitting in my garage, their eyes pop out.
And I am eagerly awaiting 4e.
