First off, nice start to your collection.  You have gotten a couple of the more difficult to acquire items (Hellbound, Conflict) out of the way.  I myself only have one of each of the items you are looking for but I am sure there are others with multiple copies that may be able to help you out.  However you should be able to pick up the Planescape box set for less than $25 fairly easily.  The Planes of Law usually goes for a bit more but if you are patient you could get it for about the same price.  Just stay away from Troll & Toad....way overpriced.

Just my 2 cents....but two sourcebooks that I consider to be the most interesting for Planescape are The Inner Planes and On Hallowed Ground.  The Inner Planes has a good amount of information on the Elemental Planes, Para-Elemental Planes, and the Positive and Negative Material Planes and the denizens who live there.  On Hallowed Ground details the deities, their followers, and their realms on the outer planes.  A lot of good information if you plan to take a group of adventurers on a jaunt across the outer planes.  You might also consider picking up Guide to the Ethereal and Guide to the Astral as they both expand on information from the core box set.

Most of the Planescape adventures are pretty decent but I find that making up your own works just as well.  One adventure that you will probably enjoy though is Dead Gods.  For one it is a huge campaign, it covers several different locations across the planes, and it has one seriously nasty bad guy named Orcus.  

First off, congrats on getting a good deal on two of the hardest to find items, And well done for picking planescape! the (imo) best setting tsr ever came up with. Unfortunately I sold any extras I had, but the planescape campaign setting usually sells for pretty cheap on Ebay.

Personally, I find the planeswalkers handbook invaluable. Most of what it contains is covered in the campain setting but the PHB is much more in depth.
I quite like the box sets, the maps are great. and of course, the adventures are all rather fun. Well of the worlds was what I used to throw my flatmates into the setting, mwahahaha. The enjoyed their romp through Baator and on into sigil.

Can't really say what I find the most useful though... I use the factols manifesto a fair bit but that's mostly because I love it and the images of the buildings in it are great for visual aids ("right, the morturary looks like this ok?") lol.

If you end up running a game keep us posted! I for one would be facinated to see what you and your players do. Hopefully they'll be less useless than my last bunch... the worst of whom I had seduced by a succubi for my own perverse enjoyment (oooo I hated him... I reaaaaally hated him)

Good luck with your collection! I just finished mine a month or so ago

wow.. what an interesting idea... well good luck to ya! Hopefully my son will be a geek... if he turns out *shudder* normal... I may have to disown him.. hahaha

flying_purple_monkfish wrote:wow.. what an interesting idea... well good luck to ya! Hopefully my son will be a geek... if he turns out *shudder* normal... I may have to disown him.. hahaha

so far my sons have been a great disappointment to me!
They should be well into rpgs by now - where did it all go wrong?!

(I have dice they can borrow   )