There are basically three models that I'm currently deciding between:
Here's a summary of the features for each:
My take on it is that the ML-2151N and ML-2152W are basically the same base model printer, but with different options. Primarily, the ML-2152W includes wireless networking.
The ML-2550 seems to be a slightly "higher end" printer (better CPU, more RAM, PostScript standard), but is the "base" model, without the extras (no NIC, no WiFi).
Right now, I'm very strongly leaning towards the first one, the ML-2550. I was looking more towards the ML-2152W, but then I found that amazing price on the ML-2550. When it was a difference of $20, it was a close call. When it's a difference of $100. . . not so close. ;-)
I wouldn't mind having built in network capabilities on the printer, but it's not a necessity. It's not that hard to hook it up to my linux server and share it via Samba. And I'm actually kind of mixed on the WiFi. . . while it'd be a rather nifty feature, I can't help but wondering at how difficult it'd be to "lock it down", so I wasn't getting random drive-by printings.
I'm probably going to order the ML-2550 tomorrow, unless I find some really good reason that I shouldn't.