Where to install D7

Is it better to install D7 in a subdir or in the root dir?

What are the advantages and disadvantages of each?

Bringing this to the top and still looking for an answer.

From a technical perspective, it should not matter whether it's installed in a sub-dir or in the main directory...

But if possible, I will always install it in the main directory as some third party modules might behave differently in sub-directory ...that's all!!!

If Dolphin will be the main site on the domain (or subdomain), then it should be installed in the root directory. In the end, though, it's your choice to make.