Still relevant to me, though not nearly as much as it was 4-8 years ago. Despite my deep loathing for the shoddy 3.5 Revision, WotC still manages to occasionally put out a book that's halfway-decent in crunch and interesting in its ideas/flavor (IMO), that I'd be willing to buy.
Once I get a new job anyway....so Tome of Battle, Draconomicon, and Lords of Madness are the few I'll snatch up copies of once I have some spending money again. Player's Handbook II is also a possibility, but I dunno.
And at least the D20 Future books are kind of cool, so I have actually bought a few WotC books in the past year or two (D20 Future, D20 Cyberscape, and D20 Future Tech). Though I still think D20 Modern kinda sucks, at least it's not hard to learn and it's easily modified. So at least I can tinker with it for different kinds of games without much trouble.