Last week I kicked off a survey about the physical layout of your databases, based on database size. I'm running it for two weeks and will report on the results next Friday.
One thing I missed was 'multiple filegroups over multiple drives/arrays/LUNs for any reason' in the > 1TB category – not enough options on the free surveys I use. If you fall into this category, use the final option on the >1TB survey and I'll lump them all together.
As of this morning there were 860 responses to the survey so far – very cool. Check it out at http://www.sqlskills.com/blogs/paul/post/Weekly-survey-does-size-really-matter-or-is-it-what-you-do-with-it.aspx.