New or used???

Jhkear,
If budget for everything is $5k (though your post explicitly states speakers only to start with), by all means spread it around. If just speakers, you will get a lot more bang for buck out of used than new.

I have bought almost everything used - speakers (twice), amps (3x), CD player (2x), preamp (1x), turntables (4x), phono (1x), crossover (1x), cables (several). The only stereo equipment I've bought new in the last 25yrs are a few odd accessories, a cartridge, a tonearm, and a phono stage. That and LOTS AND LOTS OF MUSIC.

If you want to spend your hard-earned money and keep what you buy for a long time, spend some time listening before you buy. Do a search of audio clubs in your area and see if you can't get invited to some members' homes for a listen. There are very few things which show up only once (so you can afford to wait), and there are certainly lots of choices in that price range if going used. For that money, definitely listen first. One could get large Thiels, nice Magnepans, Merlins, older Soundlabs, the Shahinian Obelisks (cheaper than $5k but I'd love to listen to them), you might find some used horns in that range, some electrostats such as Innersound or MartinLogan, and the list goes on... [disclaimer: no affiliation with anyone selling anything]

Jhkear, that clarification will help.

You did not mention what music you like and what your listening priorities are and these would help Audiogoners help you. If your like listening to electronica quite loud, and want to have your lungs vibrate a bit like on the floor of a Moscow danceclub, the 6900 and Cremonas won't cut it (but $10k is more than fine). If you like to listen to closely-miked string quartets (with ever-so-delicate phrasings) more than anything else in the world, you might consider horns (or other efficient speakers) and a low-power single-ended amplifier. There are a range of solutions in between.

I think the MA6900 is decent too, but I would listen around to see if there is anything else which floats your boat.

I also advise searching the forum archives for "$10k" or "$10,000" to see what pops up. There may be quite a few threads asking for similar advice on systems.

Jhkear, with 5k CDs, it appears as if you have your priorities sorted. Next it is simply (ha!) a matter of choosing your tools.

While I applaud Goatwuss for his supporting his friendly local dealer, those of us who use horns don't have to worry too much about the speaker port business. And anyone with those ideas playing with tube electronics has a good reason for selling anyway. If I bought new, I would be more inclined to buy direct from a manufacturer but that is my own preference and people should do what makes them most comfortable. Personally, I am happy to 'recycle' good electronics (I never would have been able to buy my system new) and be slightly scrooge-y.

As for what equipment would be good, the listening part is key. If I knew then what I know now, I would have started (and I started with a budget similar to yours, maybe a bit less) with Oris horns and some bass cabinets, some tube amps (maybe using 845 tubes for the mid and treble, and KT88s for the bass?), and for CD player, I'd be doing it on a PC (Mac actually) feeding a DAC (and to get all that for $10k, you might have to go used and DIY...). But that's just me...

Best of luck, and let us know how you get on...