Best CD player around $2000 new or used?

I'm looking to upgrade my Martin Logan/Sonic Frontiers/MIT system with a better CD player. Is an Audio Research CD-1 (used) good? How about Krell or Classe? Any recommendations?
Most definitely a used Resolution Audio CD 50 Can be found for $1500-$1800
most assuredly...
There a number of good CD players at this price point. ARCAM and CAL have new units under 2K. The Audio Research CD2 is considerably better than the CD1, although Northern Sound Co. can modify a CD1 and bring it to the CD2 level for about the same as the used cost difference between the two units. My personal feeling is that a late model ARC CD2 used is a sensational high-end value.
You're high enough, at $2000, to get a Wadia 830 if you're lucky, and IMHO it's in a completely different league from most that other responders have mentioned. I know of a particular one you might be able to get, for not more than $2100, so email me if you have a FIRM interest.
You should check out Linn Karik III's. With recent new models from Linn replacing the Karik after many years in production, people are selling almost-new Kariks for less than your price. A great choice if you are sensitive to "digital" sound, as it is very analog. It's also really well built and can be upgraded by using it as a transport. Also check out Meridian 508's, another great deal.
Meridian 506.20!!!
Save for a couple weeks more, and buy a used BAT VK-D5. Tubes! My choices were: Levinson 39 Goldmund 39xx Wadia 830 Wadia 850 Bat VK-D5 Bat's a giant killer. IMHO, and in my system it made the other coices sound ill. Best midrange and analog tonality. Try to find one to listen to if you can! Good Luck!
Mm- Try the new Cary 303 on the used market. Outstanding unit at about $1800. For the bucks, you can't beat it. Goodluck.
You should add the Rega Jupiter/Io combination to your short-list. They retail for $1800, but you can find them used for $1000-1200 (their is an ad here in Audiogon right now). Stereophile includes the Jupiter/Io in their "Class B" grouping of CD players.
If you are interested in more pedestrian brand names try an Arcam FMJ-CD23. It retails new for under $2000, runs with the big dogs in measured performance (Stereophile, my own test CDs) and sounds great. I A/B'd w/ Wadia & Theta gear and felt the Arcam was a helluva deal.
For perhaps a few $$$ more, you might be able to grab a second hand BAT VK-D5. It's a superb cd player with an absolutely stunning midrange portrayal. Highly recommended!! Good Luck Ken
I found a wadia 830 here on Audiogon for under $2000 by posting a wanted. It is a wonderful cd player. Smooth, natural and as good as,or better than anything I've heard.
I love my CD1 and I understand the CD2 is better yet. the CD2 is selling in the range you are talking about and the CD1 is normally under $1500 used. Buy one!
There are many quality CD players on the market for $2000. I have come across a few Wadia 830's and they sound beautiful. If you can come across a Anthem CD-1 you should jump at the opportunity. The CD-1 is probably the best sound for the money. Also an SFCD-1 by Sonic Frontiers is nice. I have seen a few used SFCD-1's ranging from $1500 and up, in fact I have one on auction. If you are interested, feel free to contact me.