Coming from Sourcetree, I really found SmartGit's approach dumbed down version of what Sourcetree was doing. Seriously: check that out, because it's quite good.

In most of the projects I've been working on, there is just single .gitignore in root of the project (these are usually Unity projects where the ignore is almost identical from project to project). I prefer to have single ignore file per project. I really don't want to sprinkle ignore files in random subdirectories.

It definitely should be optional, even though I actually find it actually quite pleasing to the eye!