A good way to integrate the two may be to have concept-based challenges- effects (i.e. specularity), concept (landscape, portrait), technique (making water), etc. Everyone has something they "have a knack for" that they could share. Comparitive discussions would be nice, too- to go along with the challenges- for instance, I like textures. What is the difference between a Moray texture, a Bryce, a 3ds, can they exchange, etc. What are the pros and cons of photo textures as opposed to "built". Then for the challenge- say, "skin: photo vs. procedural" or "Gone fishin'- real water looks" or similar. (I think texture is very underrated, in many cases.)