I shot 4x5 for several years, then stopped when I bought a Nikon D80 then D300. I pulled it out a few months ago and was blown away by how much more detail I get from 4x5 than I do Nikon DSLR. One thing I'll bring up is that to be really happy, you need a scanner. I just bought a used Epson V700 for $290 from eBay. I'm buying the wet mount holders from BetterScanning.com in a week or two. I'm using the stock Epson holders until then. Doing your own scanning is the way to go, I think. If you photo in a studio it won't matter so much what camera you get. If you photo outdoors much, a field camera is the thing to get. I'm once again shooting 4x5, so far only b&w.
Kent in SD