Snakebyte here. I've been reading SCP-wiki for a few months now, and finally decided to take the plunge of joining. More than anything, I've actually joined so I can vote and help edit SCP pages. Whilst I do have my ideas for objects, I think my energies could be better directed in polishing current ones.
Also a graphic designer by degree - and I think some SCPs and the foundation itself have such brilliant potential from a design standpoint. I'm really interested in peoples willing suspension of disbelief, which SCP-Wiki gets me doing all the time.
I'm a big fan of SCPs that use [REDACTED], [DATA EXPUNGED] and ████████ liberally. Ones all about what you're not saying, that as much as possible get the reader to fill in the gaps. I also like objects that are slightly innocuous, or have the potential for great power but at greater risk. Hard to pick a favourite SCP just because I enjoy so many, but I really like SCP-055