to hard to pick just one because there are so many talented players and don't want to get you bummed out if he's picked earlier so here is my top 3 I hope one of these guys drops to us.

Jared Sullinger- Very good low post scorer, rebounder on the college level. Not very athletic and only 6'8. He has been red flagged because of back concerns

NBA comparison: BBD with better low post moves and rebounding

Perry Jones III: Super athletic, great size and length, could get up and down the floor with rondo and has a nice turn around J. He has all the potential in the world, but has been very passive during his college days. If he learns to be aggressive the kid has a chance to be a all-star type

NBA Comparison: Thadeous young at the PF?
Terrence Ross
: Terrific shooter and scorer at the SG position. This is the guy that would be Ray's replacement if he leaves. He is pretty athletic and has a quick release.

NBA Comparison : Eddie Jones(Nbadraft.net)

idk a ton either but I know a bit... saying that, my dream fall picks are Jared Sullinger, Arnett Moultrie, Terrance Ross, and Perry Jones III. Its possible we get one of those guys though I wouldnt be shocked if all were taken before 21

These guys would all be my picks. Not as excited as others about sullinger but certainly wouldn't mind us getting him.

My dream fall is Terrance Ross, this guy can contribute from day one and would continue to get better. With it seeming more and more likely Ray is leaving this guy would be HUGE for us.

Another guy I just simply have a mancrush on is Arnett Moultrie lol

I will be very excited if Terrence Ross, Terrence Jones and Moe Harkless drop to us.  I'd love to get two of those. 
I'm also okay if we get Royce White, but if he's picked before us that's cool too since he'll push someone down.  I hope Sullinger, Perry Jones and Marquis Teague are all picked before our pick, pushing at least one of my favorites down.

Terrence Jones may have some question marks, but I think Rondo will help him thrive.

Terrence Ross, Tyler Zeller, Meyers Leonard, Arnett Moultrie.
The first is a SG, the latter three are Centers.

I will be very excited if Terrence Ross, Terrence Jones and Moe Harkless drop to us.  I'd love to get two of those.  
I'm also okay if we get Royce White, but if he's picked before us that's cool too since he'll push someone down.

Agree with all of what you said here.

Also, Moultrie, Perry Jones and Sullinger. And even Kendall Marshall. They're all mid-late lottery talent from what I've seen. Would be complete steals if we got them.

And indeed if Royce White, Marquis Teague or Nicholson get drafted ahead of us I'd be stoked because that means somebody is going to fall.

Worst case scenario is none of them fall but it seems the draftees are really helping us by apparently raising their draft stock. I'm scared and excited all at once.


Edit: Forgot to put in a dream fall/nightmare pick. I don't watch much (actually any) college ball but from highlights and what I've read:

Dream fall (and somewhat likely (20 on Draftexpress)): Moultrie
He's raw but he's got all the physical gifts. His defense is being criticized but from what I see it can be worked on. Being a SF before this, he's skilled and unusually quick for 6'11.

Nightmare pick: Fab Melo/Andrew Nicholson
Not exactly a nightmare but if Danny is going to draft these players I hope he pulls a Jajuan. They're not worth 21/22.

Jones would be a Blue Chip deal if he somehow got forgotten.

Unless we trade up , I'm not holding my breath.

I think the whole thing will play out minute by minute based on backup preplanned choices.  

If somebody starts a trading frenzy , with two decent picks we could get involved.

But I'm thinking, probally anti climatic. evening for Celtics, we'll just take our 3 people tommorrow and maybe deal latter.

Royce White, Terrence Ross, Jared Sullinger. I really think all three will be stars