As for #6, I'd go as far as "NEVER use include, period." I've seen about 1 actual use case out of the bazillions out there; almost certainly, require() is the droid you're looking for.
I'd also add a #10: Use E_ALL | E_STRICT , and don't ignore it. PHP is trying to tell you of many problems, shutting it up is not the right answer.
The completely brain dead naming conventions for function names (or rather, the lack thereof) is another. PHP has grown organically, just like the web, to fill a very irregular shaped niche and it shows that history in all the gory little details. That said it made me more money than any other programming language combined (including C, but it's a very close second).
Probably a lot of people have similar feelings towards Ruby, getting stuff done is what pays the bills.
I haven't seen anywhere near the same level of hate for Ruby - and I can't help thinking it's because PHP is objectively worse. A lot of the problems listed in the article wouldn't arise in a language with a better module system (such as Ruby), for example.
Even better, set error reporting to -1. This will catch every error, even if PHP devs decide to add a new type of error that isn't included in E_ALL | E_STRICT. (They already made E_STRICT not part of E_ALL, so there's no guarantee they won't do it again.)
The reason this works is because -1 is 0xFFFFFFFF.
I'd also add a #10: Use E_ALL | E_STRICT , and don't ignore it. PHP is trying to tell you of many problems, shutting it up is not the right answer.