FS Vontz,
Look at
Robert White as well for an idea of new prices, and
Aperture for secondhand. Ffordes is good, too. All three dealers are helpful if you ring them up, and I've dealt with all three. Aperture will be happy to let you try stuff out in their shop in London (Ffordes and Robert White are basically mail order, and at opposite ends of the country).
Certainly, as Juan says, think about your possible next lenses. If you're going to be shooting 21mm and 25mm 80% of the time, a viewfinder that only goes as wide as 28mm isn't going to be a good first choice. If you're going to be shooting 75mm 80% of the time, a viewfinder without 75mm framelines isn't best for you.
There's a wealth of information on the
Cameraquest site. As with any big purchase, read widely and make up your own mind.
Remember, too, that while there's a lot of angsting on every camera forum about which camera to get, THERE ARE NO CRAP M-MOUNT CAMERAS. All are good, but some are better than others for your shooting needs (different framelines for different sets of lenses, longer effective baselength - i.e., more precise rangefinder - for shooting very long or very fast lenses).