I've got a pair of AAD 2001s. They are great speakers but are quite hefty! Very dynamic, just a slight touch bright, and sound great with a lot of power. I demoed them with a ML 383, they sounded great. Hoooked up to my 4B-ST they really kick it up with great dynamics, but aren't quite as smooth as they were with the 383. Unless you're a bass head, you won't need a sub with the 2001s if you give them juice.
I've listened to N805s several times, but not the signature. The standards are a lot more laid back than the 2001s and not as good at the same price point, IMO.
I haven't heard the mini utopia, but I heard the micro in a very lousy room and they still sounded great...probably better than the 2001 but I only listened for about 10 minutes so it's hard to say, plus the micros might not be as good.
I've heard the M20s are very good, and I've heard the Gems are the best monitor out there, period, but I've not had the chance to listen.