I voted "other." As I've
advocated in the past, I'm looking for a BECMI-esque (as I understand it since I never got to experience that era) type publication scheme. My big deviation from BECMI is that I'm not looking for limits placed on level advancement, only on game complexity.
3 tiers of rulebook - "Basic," "Standard" and "Advanced"
All 3 flavors as standalone books, plus the "Basic" book in a "red box" configuration.
-Basic - Core rules for players and DMs. Enough to serve as an introduction to RPGs
AND also enough for players who want rules-light play to use this and nothing else.
Get this if you're new or like minimalist rules.
-Standard - Content of the Basic book, plus the most common optional stuff like skills, maybe feats and tactical combat, etc.
Get this if you're the average, experienced player/DM.
-Advanced - Can skip the core rules on the assumption that you have one of the previous books. The content here would be purely additional, optional rules.
Get this if you want to add the less common/more complicated optional rules.
-Standalone Monster Manual.
Get this if you're going to DM your own adventures or modify published ones.
In this model, new players/DMs get a relatively inexpensive book to start out. The rules-light crowd gets the same benefit. Experienced players/DMs will have to fork over a little more (which they're apt to do anyway) for more content. Players/DMs looking for more game complexity will have to shell out more still (which they're apt to do anyway). DMs will probably want to invest in the MM (which is still nothing new).
The one downside I see to my model is when a new player starts with Basic, decides he/she wants more and buys the Standard book (which has the redundant core rules of the Basic book). Fortunately, the Basic book -- having more longevity than a watered-down introductory product that only lasts until the included adventure is done -- should have some resale value to help defray the cost of an upgrade.