Good network printer/scanner wanted

I have a Lexmark X4550 printer/scanner/copier. I love that I can scan stuff and that it's wifi, and that it's pretty fast, but I hate so much else about it. I have been in the market for a better unit since the day I got it, but can't seem to find just the right thing.

It requires you to install a bunch of software on your computer. It's clearly not very good software, and I worry about what havoc it could be causing. It's a slow install, too. Also, there are 6 different versions, by OS. So for each computer I have to download again. And because it's big, the download is far from instant.

To scan over Wi-Fi, it goes like this:

1. load the document
2. switch to scan mode
3. browse a list of destination computers, and pick one
4. wait while it queries the computer for "applications"
• This sometimes fails after a minute
• These are things like "File, Email, Web Browser, and Computer"
• "File" brings up a custom Save As dialog on the target computer. You can't hit ENTER, you have to actually click Save. If you scan again before saving, the first scan is lost.
• "Computer" means to launch Lexmark's crappy scan touch-up software
5. select an application (I always use File)
6. click Scan Color or Scan Black 
7. wait while it scans
8. on the target computer, save the file

It has a USB port, so I can carry a laptop to it and plug in directly. This installs a second instance of the printer, which I don't really want, since I'm just trying to scan. When you do that with Windows Vista or 7, you can't use the Scan buttons any more. Instead you have to launch Windows Fax and Scan an use that interface. It's a fine interface, but it's at the computer, and scanning should happen at the scanner.

I have one pre-Vista machine, my Windows Home Server (which is based on Windows Server 2003). If I plug in to USB there, the Scan buttons follow the same sequence as Wi-Fi.

I don't scan that often, so I tolerate it, but every time I use it I am annoyed.

The print functionality is OK. The installed software insists on speaking "Printing Started" over the speakers. It sometimes fails to print with no obvious reason. Every print job asks me if I want to register, even if I check the "don't remind me again" option. It does paper jam more often than I expect, but maybe that's a hard problem.

The print & scan quality are good enough that I have no complaint.  And at my low usage level, the speed is fine.

What I really want

Small. I want something unobtrusive.

Internal paper trays. Less likely to get peanut butter on the paper.

1-touch scanning.  Load the document, click scan, and be done. The file should appear on a network share on my server ("\\SERVER\Scanned Documents").

Easy setup. On a new computer, do Add Printer -> Add network printer, and it finds it and downloads the driver from Windows Update.

Wi-Fi. I want to print from any computer in the house. But this isn't a requirement, because I could plug it in to the server and share it out there.

All-in-one isn't a requirement. I would accept a separate printer and scanner, if that's what it took. I'd even plug the scanner in to the server if that's what it took to get one-touch scanning. If they were separate units, I'd probably get a color laser from Dell Outlet, as they're not too expensive. The long-term costs are lower, as the toner doesn't age like inkjets, and I don't print much.

I've tried googling for printers, but it doesn't work. "network scanner" turns up packet sniffers. "scan to share" turns up anti-virus software.