In addition, I would consider the Marantz 5004 or 6004 and the Emotiva ERC 2.
In addition to those you're considering, I would consider the Denon 3910 or a Sony XA555ES.
The Denon players give you the option to play DVD-A, HDCD, SACD, and pretty much anything else. You can find the Denon 3910 for $250 or less all day, and there are usually 2-3 of the modified 3910's here for $5-600 (some like the APL 3910 go for much more). The 3910 was a $1500 player that plummeted in price because of blu-ray, but for audio it's still very good, and can be modified to be excellent. The stock unit would definitely save you some money and I believe is as good or better than everything in the sub-$500 price range.
The Sony sounds great as well, and gives you the flexibility to load up 5 discs at once. It's less flexible as far as format is concerned (CD/SACD), but those are going to be the go-to audiophile formats for the most part.
The Marantz and Emotiva suggestions from Rar1 are good as well. Definitely keep your options open.
One last thing to consider, especially if you're only looking for CD playback, you may find the best bet is to just buy a Sony Playstation. The PS1 (SCPH-1001) is a great and very musical CD player, and an unmodified unit shouldn't ever cost you more than $50 (there are several on eBay right now for <$30 with replacement consoles at $20). It may match with your NAD 325 better than a NAD CD player. They're really musical machines, and you could set aside an extra $400 toward your next upgrade.
I think used is the way to go to optimize your cost/performance ratio. Probably lots to choose from in your price range. Although these are older models, here are three that I can highly recommend: (1) Anthem CD-1 ($1700 MSRP, tubed output stage, decodes HDCD discs, can function as 6 disc changer); (2) California Audio Lab CL-15, CL-10 or Icon MK II (CL 15 and 10 MSRP around $1500, well built, Decodes HDCD); (3) Rega Appolo (MSRP $1000, great sound for the money, well made)
I agree with Buconero117 about the Sony SCD-CE595. However you can no longer get it from Sony or any other retailer I have found. However, I did see it on ebay for reasonable prices (none of them are mine, mine is not for sale). I had one, sold it, then bought another one because I missed it. It plays CDs, and multi-channel or 2 channel SACDs and does it very well. There are very positive reviews in several well known internet audio magazines-PFO, 6moons, and enjoy the music, just to name a few. You should read their comments as well. I highly recommend it.