I have the AGFA SnapScan Touch... lower-end but very serviceable, that I bought in 1999 or early 2000. It works fine under X 10.1, and I have a relatively underpowered Lombard 333.
AGFA recently released the scanner software Scanwise for X, and it works well. If I recall, the scanner cost about 130 bucks new.
One great thing under X is that scanning to different apps, rather than files, seems smoother, and the fact that I can print to or save to pdf right out of my Epson print dialog, or just by using Preview, is phenomenal ( I like to send a lot of my docs out as pdfs).
I was pleasantly surprised to get a tight scanning "solution" out of my AGFA so soon into the X era. ;-)
I have an Epson Perfection 1250. It's software is Classic-enabled (not native) but it works great. Installed it in Classic. When I turn the computer on (booting into OSX), the computer notes that a scanner is attached and readies it. Whenever I need to scan, I just press the button on the front and the software (from Classic) runs.
I haven't gone to their website lately to see if they have OSX-native software out there (or pending). But so far, I don't really mind.