Best speakers For ARC VT100MKII

I heard this amplifier at a friend's home driving Soundlab M1's effortlessly.
We were all amazed. Later I heard the same speaker with various other amps but none seem to match as well though they had more power.

a pair of Proac 2.5 or 3.5 or 3.8 would be great with the VT100 ... what did you find lacking the the Vandy Sig 3's though?? might help to know in order to get recommendations

Two questions:

#1: Describe the sound or performance you are seeking, as different goals and objectives (likes/dislikes) will play a significant factor.

#2: Have you done anything to maximize the performance of your room? A properly treated room will have a huge impact. You have invested in some very good equipment which can provide excellent performance. But it can also sound really crappy if the room isn't any good.

I also have a VT100MkII. I have Acoustic Zen Adagios and the combination is fantastic.

First thank you for the responses. I have a few Auralex panels around the room as needed. Nothing too drastic. Room is aprox 14 x 20. I will change rooms in the near future. What I am looking for is a speaker:
#1 That is a good pairing with my amp (type and power).

#2 One that will work in a variety or places. I found the Vandy's to be a bit too placement sensitive for me. Especially regarding the bass response

#3 A full range floor stander that will have Detailed imaging, wide soundstage, liquid midrange, deep accurate bass response that is tight and punchy when it needs to be. I really like the imaging and midrange presenc the Martin Logans. But as I said I am looking for the next step up. I listened to the newer ones and didn't like them as well as they have powered bass and they all sound like a speaker with a powered sub (to me)

I heard the Wilson Watt Puppy's and really liked them, however still a bit out my price range, thats why I was looking at B&W 804d"s or 803d's but open to any suggestions