I couldn't find a 2.1 image for the emulator, there is a 2.2 image and instructions here: http://www.ehalm.at/avd-2-2-market.php?l=en. It appears to work although it's complaining of low memory! I gave it 256Mb.
Before I did a return to factory settings, I'd bought an app that needed 2.1 and forgot to download it before my market stopped working, the 2.2 image allowed me to download it and it's now safely on my scroll.
It depends if you need it or not.
Steve