My personal whitelist:
Markaroon and Twinblade - I met these two when I was lvling my sub in dunes (since, I figured, my main (MNK) could use even more str, hp, etc from WAR before I went to grab RNG). To be blunt, it was hell for the most part. Exp was slow, all the parties I was invited to ended up being filled with newcomers to the game that "didn't know that you don't really pull a leech when there are other leeches near it" (if you catch my drift). I then PT'd with Twinblade, and his brother Markaroon was PLing everyone. PT was great, for the most part. EXP came quick, we took out enemies like it was nothing, Markaroon kept everyone alive, etc. The only downside was a beginner that...was just too...well there's just no word to describe his stupidity (when you speak english, yet don't understand "Cyclopss, you're not the puller, he is", and pulls a fly in the middle of a snipper fight...well you get the idea (his name was Cyclopss btw)).
But yeah, both of them were nice, great PL, great help, made me remember what very few good times I had in dunes the first time through.
Thebabe and Ujwood - Thebabe and her father, met them both in dunes. Thebabe is friendly, funny, and a great player overall. Ujwood is even better, a high lvl PLer who is always willing to give you that one tele you need, even if he's busy. They had to be the best combo I've ever met, past Twinblade and Mark, who have helped me a lot.
Everyone from my LS (Mainly Driskell, Psgsp, Darkskull, Lawrius, and Lsbknives from Kapoks) - From teaching me the basics, giving me a link pearl, to helping me get Kazham keys and fighting dragon, these guys were the best help I've had on this game, two thumbs up for the lot of em.
Now, I feel like adding a small blacklist:
Myself (Avelyn) - Why? Because I can admit to several occasions where I've been a complete and total jackass. I'm the type who will flip at the drop of a pin, who can get annoying quick (especially with my favorite quote, "Ho, ho, what!", if you've PT'd with me, you know), will buy out the fishing guild's supply of insect paste in one go (remember a couple weeks ago when prices went from 30gil to 60gil per piece of insect paste at fishing guild? Most of that was my fault, I went moat carp happy and bought fifteen stacks), and I tend to pull conversations toward what I want to talk about (kind of like now).
Really, I don't have many redeeming qualities. I make the funny advertising slogan (Bastok during the Doll Festival event, if you can remember the quote "Ever want to be that taru prick ******* that stole your lunch money in mage school?", that was me, I wanted to get rid of my rice cakes since they were pretty much worthless to me), and sometimes I'll help someone along (I gave someone about 10k to upgrade from the basic bronze harness set to bronze scale mail in dunes), but that's not really good enough.
Sorry, just had to rant there, judge how you will :-\