What piercing should I get next?

Pierce your left temple with an Aborigine spear.

My request is to avoid piercing. But if really want to do that, I suggest you navel piercing.

A forward helix would be really pretty, or something like a conch or snug piercing.  

If you are ok with lip piercings a medusa or a labret would look good, but be careful they can mess up your teeth/gums.  

Myfavoritelucy has the best answer, so I will not answer this.

Rather than cover your body in piercings, i would advise instead sticking with an earing in each ear, and at the end of each month, take the earings back and part exchange them for a more expensive pair, and keep doing this until you have a London by De Beers, Thames Path earring in each ear

Sounds like you have a nice piercing collection going on.  I think great additions would be multiple ear cartilage or the eyebrow.

Just because someone has piercings doesn't mean they're looking for attention. Let them do what makes them happy. I don't see how it affects you. So if you don't have anything nice to say I think you should go back to minding your own business :]

Myfavoritelucy has the best answer, so I will not answer this.

GOOD ONE LUCY!!!!!

No genital piercings?  So it's all about seeking attention with no practical value . . . . . sad.

I would skip the piercings, and go for a forehead tattoo that says 'I am SO desperate for attention, I post crap on Q&A sites'....