King Crimson is pretty close to Yes. specially in the era of Discipline and Beat, get those two, now!
Three Of A Perfect Pair should be great too, but don't have it. they got that same insane instrumentation combined with great songs, and as added ingredients, whacky lyrics (I'm wheels, I'm moving wheels! I'm a 1952 Studebacker!) and Tony Levin on Chapman Stick.
Spock's Beard is basically somewhere betwene Yes and the Beatles. it's also just that IMO. lot's of poeple love em. it's fun music tho.
Transatlantic is just some great neo-prog musicians having fun being a 70s era prog band. if you're nostalgic, you might like it. I find it a bit weak.
Flowerkings is great too. but.... I can't stand his voice
...I can take voices like Fish, LaBrie, Geddy, but Roine Stolt just doesn't cut it for me.
I think Gordian Knot is worthy of mention as well. I think they're completely instrumental, but in any case, they rock.
from Camel I would get Moonmadness, but Rajaz should be great too.
Ayreon - Into The Electric Castle. it has a bit of everything, some goth metal-ish stuff, some soundscapy stuff, some Beatle-esque stuff. just fantastic prog.
if you're going for a Pink Floyd angle, also check Pendragon (Not Of This World)
and some early Marillion ofcourse! get Script For A Jester's Tear and Misplaced Childhood if you don't already have them.