Sorry, could anyone name who is who? I get PR-T (Pretty) is a hairstyle/makeup robot, HAN-S (Hands) is that boxing (or massage) robot, VN-GO (Van Gogh) is a painter. Who else is there?
VN-GO!
I like the way he hummed “Put On Your Sunday Clothes” to WALL-E [spoil]after EVE saved him from that steward bot.[/spoil]
Apart from the ones you already said, there’s:
VAQ-M (vacuum bot)
M-O (microbe obliterater)
BR-LA (umbrella)
L-T (light)
D-FIB (defibrillator)
There are more but I can’t remember them right now.
Definitely HAN-S I love his sickness, that it can’t control its arms.
My other favorite robots would be D-FIB, and BRL-A.
Then, my fav is HAN-S 
PR-T. She’s sooooooooo funny! Plus, I like pink.
In fact, when I created my WALL•E humanizations, she was the first characer that came to mind when I got to working on the reject-bots. Her personality was so easy to put in human form! Along with the hair, makeup, and costume, of course. 
With the reject bots it’s hard to say because unlike the supporting characters in previous Pixar films it didn’t seem like you saw them enough to really know them that well, even though you get the idea of what they were built for (M-O and BURN-E had more of the spotlight so they were easier to connect to).
I would have to go with PR-T cause of the line “You look gorgeous!”.
I kind of agree with Flik-E in that the rejects don’t really have enough screen time to correctly display their personalities, but I seriously love them all just because they’re so different and definitely underappreciated.
Well, if I had to choose I’d have to say HAN-S. I dunno why, he’s probably the craziest out of them all, and I just crack up so hard whenever he’s doing something on screen. 
little chef
I like BRL-A, L-T, and VN-GO (because he paints like me!)
Since he hasn’t been said yet, I love VAQ-M. It’s such an inventive idea by PIXAR to have a vacuum cleaner with allergic reactions, and out of all the reject bots I think he looks the most realistically possible.
I voted HAN-S
I like when he [spoil] totally massacres the steward bots! [/spoil]
I like the broken PR-T bot, I have no idea why, and I’m an art person, I like the paint bot too. 
I love PR-T. I’m not sure why. I just love her.
I love M-O, too!
I love VN-GO, VAQ-M and PR-T. But they’re all adorable anyway.
I think VN-GO is by far the best
Han-S. He’s the best, you know…
PR-T is my favorite. I love her voice: “I know honey, I know!”
She’s the funniest, I just like Han-S’ attitude. Excitement and violence. Perfect.
VAQ-M
In the WALL-E soundtrack, its weird noise thing starts up in the middle of “Repair Ward” and I find it rather out of place and at the same time very awesome.
I voted for BRL-A because of a really good fan-fic I read.