Yes, WotC is relevant to me. I always try to support Necromancer Games, Goodman Games, Green Ronin, and Paizo FIRST since they generally have smaller print runs and actually need the support a little more. Smaller print runs mean that their product is harder to find once it goes OOP. WotC books will always be easy to find (and reasonably priced) even years after its been published, so buying WotC is less of a priority for me. This works out well since I can check out reviews first (thank you ENWorld) and be more selective.
Believe me, I'd be happy to write off WotC if their product was shoddy (especially after they killed Dragon and Dungeon), but about half of what they make seems to be pure gold. I'm just glad I'm not a completist. For example, I love the Monster Manuals, Draconomicon, Libris Mortis, Lords of Madness, DMG II, PHB II, Spell Compendium, Magic Item Compendium, Slaughterguarde, Ravenloft, and Red Hand of Doom. Those titles are wonderful! I plan to purchase the Forgotten Realms trilogy, Dungeonscape, and their books on Demons and Devils since they sound like the quality. I also have tons of DDMs, but generally prefer Reaper's sculpts.
Plus, WotC recruits writers from these smaller companies. They often borrow their ideas too, and incorporate the best. WotC must be as relevant as these other companies, since they all are kind of in this mess together, you know?